COLLAPSING  PRESSURES 

OF 

LAP- WELDED  STEEL  TUBES 


BY 

PROF.  REID  T.  STEWART 

MEMBER  OF  THE  SOCIETY 

Western  University , Allegheny,  Pa. 


A PAPER  READ  AT  THE  CHATTANOOGA  MEETING,  MAY,  1906 


JUL  2 S 1924 

UNIVERSITY  OF  ILLINOIS 

1906 

PUBLISHED  BY  THE  SOCIETY 

12  W.  31st  Street,  New  York,  N.  Y. 


G%0  ' II  EtlGlUtEKiUG  UtiilMi 

4-Cx 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  3 


Wo.  1116.* 

COLLAPSING  PRESSURES  OF  BESSEMER  STEEL  LAP- 
WELDED  TUBES,  THREE  TO  TEN  INCHES  IN 
DIAMETER. 


BY  PROF.  REID  T.  STEWART,  PITTSBURG,  PA. 

(Member  of  the  Society.) 

Abstract. 

This  research  was  undertaken  for  the  purpose  of  supply- 
ing an  urgent  demand  for  reliable  information  on  the  behavior 
of  modern  wrought  tubes  when  subjected  to  fluid  collapsing  pres- 
sure. Every  means  known  to  engineering  science  that  could  aid 
in  the  accomplishment  of  this  undertaking  has  been  used,  and 
every  possible  effort  made  to  get  at  the  truth  and  have  the  research 
yield  trustworthy  data.  It  was  planned  and  executed  under  the 
immediate  direction  of  the  author,  at  the  McKeesport  works  of  the 
National  Tube  Company,  and  has  occupied  for  its  completion, 
during  a period  of  four  years,  the  time  of  from  one  to  six  men. 

Series  One . — This  series  of  tests  was  made  on  tubes  that  were 
8f  inches  outside  diameter,  for  all  the  different  commercial  thick- 
nesses of  wall,  and  in  lengths  of  2±  5,  10,  15  and  20  feet  between 
transverse  joints  tending  to  hold  the  tube  to  a circular  form.  The 
chief  purpose  of  this  series  of  tests  was  to  furnish  data  for  deter- 
mining which  of  the  existing  formulae,  if  any,  were  applicable 
to  modern  lap-welded  steel  tubes,  especially  when  used  in  com- 
paratively long  lengths,  such  as  well  casing,  boiler  tubes  and  long 
plain  flues. 

Series  Two. — This  series  of  tests  was  made  on  single  lengths  of 
20  feet  between  end  connections,  tending  to  hold  the  tube  to  a cir- 
cular form.  Seven  sizes,  from  3 to  10  inches  outside  diameter, 
and  in  all  the  commercial  thicknesses  obtainable,  have  been  tested 
to  date.  The  chief  purpose  of  these  tests  was  to  obtain,  for  com- 
mercial tubes,  the  manner  in  which  the  collapsing  pressure  of  a 
tube  is  related  to  both  the  diameter  and  thickness  of  wall. 

* Presented  at  the  Chattanooga,  Tennessee,  Meeting  (May,  1906)  of  the  Ameri- 
can Society  of  Mechanical  Engineers  and  forming  part  of  Volume  27  of  the 
Transactions. 


4 COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

Inapplicability  of  Previously  Published  Formulae. — Prepara- 
tory to  entering  upon  the  present  research  all  existing  published 
formulae  that  could  be  found  were  collected,  and,  after  the  com- 
pletion of  Series  One,  were  tested  as  to  their  applicability  to  mod- 
ern steel  tubes.  Among  the  formulae  thus  tested  were  two  each 
by  Eairbairn,  Unwin,  Wehage  and  Clark,  and  one  each  by  Nys- 
trom,  Grashof,  Love,  Belpaire,  and  the  Board  of  Trade  (British), 
all  of  which,  with  possibly  two  exceptions,  appear  to  be  based 
upon  Fairbairn’s  classical  experiments  made  more  than  a half 
century  ago,  upon  tubes  wholly  unlike  the  modern  product.  With- 
out exception,  all  of  these  formulae,  when  thus  tested,  proved  to 
be  inapplicable  to  the  wide  range  of  conditions  found  in  modern 
practice.  As  an  illustration  of  this,  the  very  first  tube  tested  in 
connection  with  this  research  failed  under  a pressure  that  exceeded 
by  about  300  per  cent,  that  calculated  by  means  of  Fairbairn’s  for- 
mula. 

Results  of  Present  Research. — The  principal  conclusions  to  be 
drawn  from  the  results  of  the  present  research  may  be  briefly  stated 
as  follows : 

1.  The  length  of  tube,  between  transverse  joints  tending  to  hold 
it  to  a circular  form,  has  no  practical  influence  upon  the  collapsing 
pressure  of  a commercial  lap-welded  steel  tube  so  long  as  this 
length  is  not  less  than  about  six  diameters  of  tube.  (Pp.  32,  40.) 

2.  The  formulae,  as  based  upon  the  present  research,  for  the 
collapsing  pressures  of  modern  lap-welded  Bessemer  steel  tubes, 
are  as  follows : 


P = 1,000  (l  - 

Vl  - 1,600  J)  . . 

• • (A) 

P = 86,670  2 

- 1,386  

• • (B) 

Where  P = collapsing  pressure,  pounds  per  sq.  inch. 
d = outside  diameter  of  tube  in  inches. 
t = thickness  of  wall  in  inches. 


Formula  A is  for  values  of  P less  than  581  pounds,  or  for  values 
of  4 less  than  0.023,  while  formula  B is  for  values  greater  than 

CL 

these. 

These  formulae,  while  strictly  correct  for  tubes  that  are  20  feet 
in  length  between  transverse  joints  tending  to  hold  them  to  a cir- 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  5 

cular  form,  are,  at  the  same  time,  substantially  correct  for  all 
lengths  greater  than  about  six  diameters.  They  have  been  tested 
for  seven  sizes,  ranging  from  3 to  10  inches  outside  diameter,  in 
all  obtainable  commercial  thicknesses  of  wall,  and  are  known 
to  he  correct  for  this  range. 

For  the  convenience  of  those  who  wish  to  apply  these  formula 
to  practice  a table  has  been  calculated,  giving  the  collapsing  pres- 
sures of  all  the  commercial  sizes  of  lap-welded  tubes  from  2 to  11 
inches  outside  diameter.  (See  p.  84.) 

For  those  who  prefer  graphical  methods  charts  have  been  con- 
structed, for  use  of  which  see  pp.  89,  92. 

When  applying  these  formulae,  tables  and  charts  to  practice, 
it  should  be  remembered  that  a suitable  factor  of  safety  must  be 
applied,  which  should  not  he  less  than  from  3 to  6,  see  p.  88. 

3.  The  apparent  fiber  stress  under  which  the  different  tubes 
failed  varied  from  about  7,000  pounds  for  the  relatively  thinnest 
to  35,000  pounds  per  square  inch  for  the  relatively  thickest  walls. 
Since  the  average  yield  point  of  the  material  was  37,000  and  the 
tensile  strength  58,000  pounds  per  square  inch,  it  would  appear 
that  the  strength  of  a tube  subjected  to  a fluid  collapsing  pressure 
is  not  dependent  alone  upon  either  the  elastic  limit  or  ultimate 
strength  of  the  material  constituting  it.  (See  p.  73.) 


Introduction. 

The  planning  and  execution  of  this  research  was  rendered 
especially  difficult  because  of  the  lack  of  any  reliable  data  bearing 
upon  the  behavior  of  modern  wrought  tubes  when  subjected  to  a 
fluid  collapsing  pressure.  Fairbairn’s  experiments,  made  more 
than  a half  century  ago  on  tubes  unlike  the  modern  product,  were 
of  such  a character  as  not  to  furnish  suitable  data  for  the 
planning  of  a similar  but  much  more  elaborate  research  on 
modern  tubes.  Aside  from  the  numerous  formulse,  some  ten 
or  twelve  in  number,  based  practically  upon  Fairbairn’s  ex- 
periments, and  therefore  not  to  he  seriously  considered  in  this 
connection,  the  only  available  data  consisted,  so  far  as  could 
be  discovered,  of  a few  isolated  experiments  on  flues  and 
several  records  of  the  condition  under  which  tubes  and  flues 
have  failed  in  service,  together  with  a table  of  computed  collapsing 
pressures  published  in  a well-known  handbook,  whose  origin  could 
not  be  traced.  As  an  illustration  of  the  utter  unreliability  of  ex- 


6 COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

i sting  data  on  this  subject,  at  the  commencement  of  this  research, 
the  very  first  wrought  tube  tested  failed  at  a pressure  that  ex- 
ceeded by  about  300  per  cent,  that  calculated  by  means  of  Fair- 
bairn’s  formulae. 

The  experimental  part  of  this  research  was  carried  out  under 
the  immediate  direction  of  the  author  at  the  National  Department 
of  the  National  Tube  Company,  McKeesport,  Pa.  He  is  greatly 
indebted  to  the  officials  of  the  National  Department  for  the  courtesy 
shown  him,  especially  to  the  manager,  Mr.  G.  G.  Crawford,  to  the 
superintendent  of  the  tube  mills,  Mr.  A.  M.  Saunders,  and  to  Mr.  J. 
A.  McCulloch,  in  whose  department  the  special  apparatus  was  con- 
structed and  the  experiments  conducted.  The  great  interest  in  the 
work  shown  by  Mr.  McCulloch  and  his  many  valuable  suggestions 
as  the  work  progressed  were  of  inestimable  value.  All  the  author’s 
wishes  in  the  matter  have  been  cheerfully  carried  out,  the  Tube 
Company  generously  providing  every  needful  facility  for  carrying 
on  the  research  in  a most  thorough  manner. 

The  exceptional  consistency  of  the  results  obtained,  taking  all 
things  into  consideration,  are  due  in  a large  measure  to  the  care 
with  which  the  author’s  assistants,  Messrs.  H.  G.  Wardale,  H.  E. 
Williams  and  J.  N.  Kinney,  have  done  their  work;  and  the  value  of 
the  final  conclusions  are  due  largely  to  Messrs.  E.  E.  Shanor  and  F. 
P.  Kramer,  who  have,  under  his  immediate  direction,  deduced  the 
formulae  representing  the  results  of  the  experiments  and  prepared 
the  tables,  charts  and  drawings  contained  in  the  body  of  this 
paper.  It  is  due  Mr.  Shanor  to  state  that  the  greater  part  of  this 
work  has  been  done  by  him. 

The  original  Log  of  Tests  comprises,  in  addition  to  what  has 
been  abstracted  for  this  paper,  a complete  file  of  autographic 
calipering  diagrams,  photographs  showing  two  views  of  each  tube 
after  being  collapsed,  impressions  from  the  collapsed  sections,  and 
remarks  on  each  individual  test.  The  complete  record  fills  two 
quarto  volumes,  each  about  five  inches  thick,  and,  in  addition,  the 
matter  resulting  from  working  up  this  data  in  order  to  get  the  final 
results  obtained  are  sufficient  to  fill  a third  volume. 

All  this  matter  has  been  carefully  worked  over  for  this  paper 
and  condensed  into  the  form  of  tabulated  results  and  charts  show- 
ing the  consistency  of  the  results  obtained,  and  at  the  same  time 
revealing  to  the  eye  the  laws  involved. 

While  much  has  been  necessarily  omitted,  it  is  hoped  that 
enough  has  been  given  to  convince  the  engineer  or  artisan,  who 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  7 


may  have  use  for  them,  of  the  trustworthiness  of  the  final  con- 
clusions. 


Preliminary  Considerations. 

While  planning  this  research  it  was  assumed  that  the  resistance 
offered  by  a tube  to  an  external  fluid  pressure  would  depend  upon 
the  following  five  things,  namely : 

1.  The  diameter  of  the  tube. 

2.  The  length  of  tube  between  transverse  joints  or  end  con- 
nections tending  to  hold  it  to  a circular  form. 

3.  The  thickness  of  the  wall. 

4.  The  deviation  of  the  tube  from  perfect  roundness. 

5.  The  physical  properties  of  the  material  of  which  the  tube 
is  made. 

Of  these  five  things  that  may  vary  it  was  thought  that,  for  the 
preliminary  experiments,  at  least,  Nos.  4 and  5 would  be  prac- 
tically constant;  No.  4,  because  the  tubes  being  all  made  by  the 
same  process,  would  probably  run  fairly  uniform  as  to  deviation 
from  roundness,  and  No.  5,  because  the  material  in  this  case  being 
Bessemer  tube  steel,  is  known  to  run  fairly  uniform  in  its  physical 
properties.  The  physical  tests  would,  of  course,  serve  as  a check 
upon  this  latter. 

The  only  variation,  then,  to  be  expected  in  Nos.  4 and  5 would 
be  that  due  to  the  inability  of  the  manufacturer  to  turn  out  a 
uniform  product.  It  is  recognized  here  that  the  physical  properties 
of  rolled  steel  depend  in  some  measure,  other  things  being  equal, 
upon  the  thickness  of  the  plate;  or,  in  this  case,  upon  the  thick- 
ness of  the  wall  of  the  tube.  It  is  clear  that  any  variation  of  this 
nature  would  be  a function  of  the  thickness,  and  would  conse- 
quently be  taken  care  of  in  an  empirical  formula  by  the  quantity 
representing  the  thickness. 

All  the  published  formulae  bearing  upon  the  subject  indicated 
that  the  diameter  and  thickness  of  wall  has  each  an  important 
determining  influence  on  the  collapsing  pressure  of  a tube;  and 
since  there  were  the  best  of  theoretical  reasons  for  believing  this 
to  be  the  case,  it  was  of  course  decided  to  plan  the  research  to  dis- 
cover, if  possible,  the  precise  nature  of  this  influence  over  a wide 
commercial  range. 

The  influence  of  length  of  tube,  between  transverse  joints,  or 
end  connections  tending  to  hold  it  to  a circular  form,  upon  the 
collapsing  pressure,  appeared,  in  the  light  of  available  data,  to 


8 COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

be  the  most  uncertain  of  all  the  variables  entering  the  problem. 
It  was  therefore  decided,  first  of  all,  to  determine  the  precise  na- 
ture of  this  influence. 

In  order  to  do  this  the  following  apparatus  was  used,  the  greater 
part  of  which  was  especially  constructed  for  this  research : 

Hydraulic  Test  Apparatus. 

The  production  of  a suitable  apparatus  in  which  to  subject  the 
tubes  to  an  external  fluid  pressure,  and  at  the  same  time  handle 
with  expedition  the  large  number  of  tests  contemplated,  was  a 
somewhat  difficult  problem  to  solve.  After  much  consideration  of 
the  matter  the  scheme  illustrated  in  Tig.  1 was  adopted. 

It  will  be  seen  by  reference  to  this  figure  that  the  scheme  pro- 
vides for: 

1.  A test  cylinder  with  one  head  removable  for  the  reception 
of  the  tube  to  be  tested,  this  cylinder  being  provided  with  means 
for  creating  an  hydraulic  pressure  within,  thus  subjecting  the 
tube  under  test  to  a fluid-collapsing  pressure. 

2.  A low  pressure  water  supply,  L , of  large  volume  to  rapidly 
fill  the  space  within  the  test  cylinder  not  occupied  by  the  tube 
under  test. 

3.  A variable  high  pressure  water  supply,  H,  furnished  by  an 
hydraulic  pressure  pump,  P , the  purpose  of  which  was  to  create  a 
fluid  pressure  within  the  test  cylinder,  the  tube  under  test  by 
this  means  being  subjected  to  a gradually  increasing  fluid-col- 
lapsing pressure. 

4.  A set  of  pressure  gauges,  B,  C,  T>,  having  a large  range  in 
capacity,  connected  so  that  they  could  be  used  either  singly  for 
indicating  the  fluid  pressure  within  the  test  cylinder  or  in  com- 
bination for  comparison. 

5.  A vent  pipe,  V,  leading  from  the  interior  of  the  tube  under 
test  through  the  head  of  the  test  cylinder  to  the  atmosphere,  in 
order  to  maintain  constantly  an  atmospheric  pressure  within  the 
tube  being  tested. 

6.  An  air  vent,  E,  connecting  with  the  highest  point  of  the  in- 
terior of  the  test  cylinder,  in  order  to  thoroughly  free  it  from  air 
while  being  filled  with  water,  after  the  insertion  of  a tube  to  be 
tested. 

In  addition  to  the  above,  while  carrying  out  this  scheme,  de- 
vices were  in  use  for  manipulating  the  removable  head,  and  for 
handling  the  tubes  while  being  entered  and  withdrawn,  but  in 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


-Sixteen-inch^Hydraulic  Test  Apparatus.  Especially  Designed  and  Constructed  for  Collapsing  Tests  on  Tubes, 

Conducted  by  Prof.  R.  T.  Stewart. 


10  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

order  not  to  encumber  the  paper  with  unessential  details  no  men- 
tion of  these  will  be  made. 

Sixteen-Inch  Test  Cylinder. — This  cylinder  as  originally  con- 
structed was  made  up  of  three  sections,  whose  aggregate  length 
approximated  45  feet,  the  intention  being  to  have  it  long  enough 
to  accommodate  a string  of  well  casing  consisting  of  either  two 
full  lengths  of  20  feet  each,  including  three  couplings,  or  one  full 
length  of  20  feet,  with  a half  length  coupled  to  each  of  its  ends. 
It  was  soon  discovered  that  the  behavior  of  a tube  in  collapse  was 
such  that  precisely  the  same  results  could  be  had  from  a single 
20-foot  length  as  from  either  of  the  above  arrangements.  Because 
of  this  the  cylinder  was  shortened  at  the  first  opportunity,  by  the 
removal  of  the  intermediate  section,  to  a length  of  about  30  feet. 

The  sections  of  this  test  cylinder  were  made  from  Bessemer 
steel  lap-welded  tubes,  16  inches  outside  diameter  and  three-quar- 
ters inch  thick,  to  which  steel  flanges  were  welded  for  the  inter- 
mediate joints.  Thickening  rings  were  welded  to  the  ends  in- 
tended to  be  threaded  for  the  attaching  of  the  heads. 

The  highest  fluid  pressure  reached  in  this  test  cylinder  was  in 
connection  with  the  retest  of  No.  418,  which  failed  under  a fluid 
pressure  of  2,890  pounds  per  square  inch.  This  corresponds  to 
a stress  of  28,000  pounds  per  square  inch  in  the  wall  of  the  cylin- 
der. This  was  about  as  near  the  yield  point  of  the  material  con- 
stituting the  cylinder  as  it  was  thought  prudent  to  go,  so  that 
all  tests  at  higher  fluid  pressures  were  made  in  the  8-inch  test 
cylinder,  which  was  relatively  about  twice  as  strong. 

The  heads  for  the  16-inch  test  cylinder  were  made  from  cir- 
cular blanks  punched  from  steel  plates  2^  inches  thick,  and  pressed 
into  shape,  while  hot,  by  means  of  an  hydraulic  press.  They  were 
then  fitted  to  the  ends  of  the  test  cylinder,  which  had  been  re- 
enforced in  the  manner  already  described,  by  means  of  trapezoidal 
threads  designed  so  as  to  best  resist  stress  in  one  direction.  In 
the  retest  on  No.  418  these  threads  were  subjected  to  a shearing 
stress  of  666,000  pounds. 

The  flange  joints  connecting  the  different  sections  of  the  test 
cylinder  were  tongued  and  grooved,  and  were  made  up  with  leather 
packing  in  the  bottom  of  the  grooves.  These  joints  each  con- 
tained eighteen  lf-inch  steel  bolts,  and  were  fully  as  strong  against 
internal  fluid  pressure  as  the  wall  of  the  cylinder. 

Means  of  Filling  Test  Cylinder. — The  rear  end  of  the  test  cylin- 
der was  connected,  in  the  manner  shown  in  Big.  1,  to  the  low 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  11 

pressure  water  supply,  L , of  the  works,  for  the  purpose  of  rapidly 
filling  the  space  within  the  cylinder  and  surrounding  the  tube 
under  test.  By  this  means  the  test  cylinder  was  quickly  filled  with 
water,  the  pressure  within  being  maintained  constantly  an  atmos- 
pheric pressure  by  means  of  the  air  vent,  E , shown  at  the  top  of 
the  left  hand  head.  This  vent  also  served  the  purpose  of  entirely 
freeing  the  cylinder  from  imprisoned  air,  thus  reducing  to  a mini- 
mum the  distortion  of  the  tube  under  test  when  failure  occurred, 
and  also  rendering  a serious  accident  to  the  attendants  impossible 
in  case  rupture  of  the  cylinder  wall  should  occur  while  making  a 
test. 

Hydraulic  Pressure  Pum,p. — The  pressure  within  the  test  cylin- 
der was  created  by  means  of  an  hydraulic  pressure  pump  capable 
of  working  against  a fluid  pressure  up  to  3,000  pounds  per  square 
inch.  Ordinarily  this  pump  was  operated,  upon  entering  the 
region  of  expected  collapse,  so  as  to  increase  the  fluid  pressure  at 
a rate  of  from  about  2 to  10  pounds  per  second,  depending  upon 
the  gauge  used.  At  these  rates  of  increase  of  pressure  the  con- 
ditions were  favorable  for  the  making  of  an  exact  determination 
of  the  fluid  pressure  under  which  the  tube  failed. 

Pressure  Gauges. — The  gauges  used  for  indicating  the  pressure 
at  instant  of  collapse  were  three  Shaw  differential-piston  mer- 
cury gauges,  having  capacities  of  1,000,  3,000  and  8,500  pounds 
per  square  inch.  They  were  connected  in  the  manner  shown  in 
Fig.  1,  so  that,  by  opening  or  closing  suitable  valves,  any  one  or 
more  of  them  could  be  connected  to  the  test  cylinder  for  the  pur- 
pose of  indicating  the  pressure  therein.  They  could  also  he  in- 
terconnected for  the  purpose  of  comparing  their  scale  readings  at 
different  pressures. 

The  matter  of  selecting  a suitable  type  of  gauge  for  this  research 
was,  at  the  start,  given  due  consideration.  Spring  gauges,  owing 
to  their  liability  to  become  deranged  when  once  calibrated,  were 
not  to  he  considered,  and  a mercury  column  for  the  high  pressure 
expected  was  out  of  the  question.  After  considering  various  forms 
of  dead-weight  testers  and  high-pressure  manometers,  it  was  de- 
cided to  use  the  Shaw  differential-piston  mercury  gauge.  This 
gauge  is  in  reality  a mercury  column  shortened,  for  all  pressures, 
to  a length  of  about  three  feet,  by  the  introduction  of  differential 
pistons.  These  pistons  are  very  ingeniously  provided  with  soft 
rubber  disks,  placed  so  as  to  render  them  absolutely  fluid-tight,  and 
at  the  same  time  practically  frictionless.  With  clean  pistons  and 


12  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

new  rubber  disks  these  gauges  were  sensitive  and  in  every  respect 
reliable. 

For  the  service  required  of  them  in  connection  with  this  research, 
these  gauges  were  superior  to  the  usual  hydraulic  spring  gauge  in 
three  very  important  respects,  namely: 

1.  The  scale  of  the  Shaw  mercury  gauge  as  compared  with  that 
of  the  hydraulic  spring  gauge  can  be  read  with  about  three  times 
the  accuracy,  that  is,  the  error  of  scale  reading  is  only  about  one- 
third  that  of  the  ordinary  spring  gauge  of  the  same  capacity. 

2.  Since  this  gauge  is  in  reality  a shortened  mercury  column,  it 
is,  when  properly  constructed,  as  reliable  as  the  latter.  In  this 
respect  it  bears  the  same  relation  to  the  spring  gauge  as  the  mer- 
curial barometer  does  to  the  aneroid.  It  lacks,  of  course,  the 
closeness  with  which  pressures  may  be  read  on  a mercury  column 
just  in  proportion  to  the  relative  lengths  of  their  respective  scales. 

3.  The  Shaw  gauge  is  practically  free  from  the  vibrations  that 
are  often  so  annoying  when  using  a spring  gauge.  This  property 
of  the  mercury  gauge  rendered  it  eminently  serviceable  in  this  con- 
nection, since  it  was  necessary  to  create  the  fluid  pressure  by  means 
of  a plunger  pump  without  an  air  cushion. 

! Eight-Inch  Test  Cylinder. — This  smaller  cylinder  was  con- 
structed for  the  purpose  of  testing  the  3 and  4-inch  tubes,  and  all 
of  these  sizes  were  tested  in  it  with  the  exception  of  Nos.  462  and 
464-469.  This  test  cylinder  was  made  up  from  a single  20-foot 
length  of  8-inch  double  extra  strong  pipe,  8f  inches  outside  di- 
ameter, and  J-inch  wall. 

The  details  of  one  end  of  this  cylinder,  with  tube  under  test  in 
place,  are  shown  in  Fig.  2,  the  other  end  being  an  exact  dupli- 
cate of  the  one  shown.  It  will  be  observed  that  this  apparatus 
is  arranged  so  as  to  permit  of  testing  a plain  end  tube,  with  the 
ends  open  to  the  atmosphere  and  the  interior  of  the  tube  exposed 
to  view  while  under  test.  In  this  way  the  tube  while  under  test 
is  entirely  relieved  of  any  longitudinal  stress  due  to  the  fluid 
pressure  surrounding  it.  The  sectional  view,  Fig.  2,  shows  clearly 
the  construction  of  the  cylinder.  It  will  be  observed  that  the  tube 
is  held  in  place  within  the  test  cylinder  by  steel  centering  rings,  A, 
one  at  each  end,  while  the  cup  leather  packing  rings  are  being 
slipped  in  place  over  the  ends  of  the  tube  to  be  tested.  This  leather 
packing  ring,  at  each  end  of  the  test  cylinder,  is  backed  by  a cast 
iron  ring,  B , that  fills  the  space,  as  shown,  between  the  inner  sur- 
face of  the  end  of  the  test  cylinder  and  the  outer  surface  of  the  end 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


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14  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

of  the  tube  under  test.  This  latter  ring  is  held  in  place  by  means 
of  a steel  sleeve,  C , engaging  its  outer  surface  by  means  of  an  in- 
ternal flange,  and  which  is  attached  to  the  end  of  the  test  cylinder 
by  means  of  the  trapezoidal  threads  shown. 

A plug,  D , was  inserted,  as  shown,  near  each  end  of  the  experi- 
mental tubes  for  the  purpose  of  preventing  the  centering  ring  and 
packing  from  being  damaged  and  the  attendant  difficulty  of  re- 
moval of  tube  that  might  result  from  the  tube  collapsing  in  the 
end  connections.  Since  a commercial  tube  is  more  apt  to  collapse 
at  or  near  one  end  than  near  the  middle  of  its  length,  this  simple 
expedient  made  it  possible  to  conduct  the  experiments  without  the 
frequent  delays  that  would  have  otherwise  resulted  from  the  jam- 
ming of  the  tube  in  the  end  connections. 

This  smaller  test  cylinder  was  placed  over  and  was  supported 
by  the  larger  one.  It  was  connected  to  the  same  set  of  pressure 
gauges,  and  was  operated,  in  every  essential  respect,  precisely  as 
was  the  larger  apparatus. 

In  order  to  get,  with  the  apparatus  available  for  the  purpose, 
a fluid  pressure  equal  to  the  greatest  working  capacity  of  this  cylin- 
der, it  became  necessary  to  couple  up  in  series  two  hydraulic 
pressure  pumps,  each  of  3,000  pounds  capacity,  so  that  the  second 
pump  could,  if  desired,  deliver  water  to  the  test  cylinder  under 
fluid  pressures  up  to  6,000  pounds  per  square  inch.  The  highest 
pressure  attained  in  this  apparatus  was  5,625  pounds  per  square 
inch  fluid  pressure,  which  was  had  while  testing  Hos.  476  and  477. 

Test  Heads , Supports  and  Vents. — The  different  styles  of  test 
heads  used,  the  manner  of  supporting  the  tube  in  the  test  cylinder, 
and  the  vent  pipes  connecting  the  interior  of  the  tube  under  test 
with  the  atmosphere,  are  clearly  shown  in  Tigs.  3 to  5. 

The  Coupled  Test  Heads , as  shown  in  Tigs.  1 and  3,  were 
made  up  from  short  lengths  of  tubing  of  the  same  diameter  and 
thickness  of  wall  as  that  of  the  tube  placed  under  test.  One  end 
of  this  test  head  was  threaded  like  the  tube  under  test,  the  two 
being  connected  by  means  of  a standard  sleeve  coupling,  in  pre- 
cisely the  same  manner  as  two  sections  of  the  same  tubing  would 
be  connected  in  practice,  as,  for  example,  in  the  case  of  a string 
of  well  casing.  The  other  end  of  each  of  these  test  heads  was 
closed  by  having  a steel  disk  inserted  into  its  end  and  welded  in 
place,  the  closed  end  of  the  left-hand  test  head  being  drilled  and 
tapped  for  the  reception  of  the  end  of  the  vent  pipe  for  maintain- 
ing atmospheric  pressure  within  the  tube  under  test,  as  shown. 


Air  Vent 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  3. — Experimental  Tube  with  Coupled  Test  Head  shown  in  Position  in  16"  Hydraulic  Test  Cylinder. 
This  Style  of  Head  is  Marked  “ a ” in  the  Tabular  Statements. 


16  COLLAPSING-  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

This  style  of  test  head  was  used  for  all  the  tests  of  Series  One 
and  for  such  portions  of  Series  Two  as  contain  the  letter  “ a ” 
opposite  in  column  33  of  the  tabular  statement  of  principal  results 
of  tests. 

This  method  of  closing  the  ends  of  the  experimental  tubes,  aside 
from  the  annoyance  of  an  occasional  collapse  of  the  head  itself, 
while  entirely  satisfactory  in  other  respects,  proved  to  be  both 
slow  and  expensive  to  carry  out  with  the  facilities  at  hand  for 
making  up  the  experimental  tube  before  testing,  and  for  the 
removal  of  the  heads  after  failure  had  occurred.  Until  it  was 
discovered  that  the  influence  upon  the  collapsing  pressure  due  to 
the  tendency  of  the  end  connections  of  a tube  to  hold  it  to  a 
circular  form,  ceased  to  be  measurable,  for  a commercial  tube, 
at  a distance  along  its  length  from  either  end  of  from  3 to  4 diam- 
eters, this  style  of  test  head  apparently  possessed  the  merit  of 
subjecting  the  tube  under  test  to  the  same  kind  of  end  support 
as  that  actually  existing  in  a string  of  well  casing. 

After  this  fact  was  fully  established  the  less  expensive  and 
otherwise  more  satisfactory  methods  below  described  were  used. 

The  Bolted  Test  Head , Fig.  4,  was  suggested  by  the  appliance 
commonly  used  by  tube  works  for  the  testing  of  tubes.  In  the 
commercial  testing  of  tubes  it  is  invariably  the  practice  to  subject 
the  tube  to  an  internal  or  bursting  pressure;  whereas,  in  connec- 
tion with  this  research,  an  external  or  collapsing  pressure  was 
applied. 

This  test  head  (Fig.  4)  consisted  of  a casting  with  a circular 
groove  cut  into  its  face  for  the  reception  of  the  plain  end  of 
the  experimental  tube.  At  the  bottom  of  this  groove  was  inserted 
suitable  packing  for  the  production  of  a water-tight  joint  when  the 
head  is  firmly  pressed  against  the  end  of  the  tube.  The  two 
through  bolts  shown  were  intended  merely  to  hold  the  two  heads 
in  place  and  create  sufficient  initial  pressure  to  prevent  leakage 
at  the  start  of  the  test,  the  external  fluid  pressure  being  relied  upon, 
during  the  continuance  of  the  test,  for  maintaining  a tight  joint 
between  the  test  head  and  the  end  of  the  tube. 

These  test  heads  were  each  provided  with  two  small  rollers  for  the 
purpose  of  making  easier  the  handling  of  the  experimental  tubes 
while  being  inserted  and  withdrawn  from  the  hydraulic  test  cylin- 
der. The  left-hand  head  was  drilled  and  tapped,  as  shown,  for 
the  reception  of  the  end  of  the  vent  tube.  The  vent  tube  for  con- 
stantly maintaining  an  atmospheric  pressure  within  the  tube  under 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  17 


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18  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


COLLAPSING  PRESSURES  OF  LAP- WELDED  STEEL  TUBES.  19 


test,  for  this  style  of  test  head,  was  coiled  into  the  form  of  a spiral 
spring,  in  order  to  give  it  greater  flexibility.  This  style  of  test 
head  was  used  for  all  those  experimental  tubes  of  Series  Two  that 
are  marked  “ b ” opposite,  in  column  33  of  the  tabular  state- 
ments. 

The  Press  Fitted  Test  Head , as  shown  in  Fig.  5,  was  used  for 
the  experimental  tubes  of  Series  Two  that  are  marked  “ c ” oppo- 
site in  column  33  of  the  tabular  statements.  This  was  the 
simplest  of  all  the  devices  tried  for  closing  the  ends  of  the  experi- 
mental tubes.  These  heads  consisted  of  iron  castings,  grooved,  as 
shown,  for  the  reception  of  the  ends  of  the  experimental  tubes. 
These  grooves  were  close-fitting  on  the  sides  and  contained  pack- 
ing at  the  bottom,  thus  forming  a very  satisfactory  joint  that 
became  stancher  as  the  external  fluid  pressure  upon  the  tube  under 
test  increased. 

The  Vent  Pipes  for  maintaining  constantly  an  atmospheric 
pressure  within  the  tube  under  test,  while  the  external  fluid 
pressure  upon  it  was  being  gradually  increased,  are  clearly  shown 
in  Figs.  3-5.  For  the  coupled  test  head,  where  the  experimental 
tube  was  held  central  in  the  hydraulic  test  cylinder,  the  vent  pipe 
consisted  of  a 1^-inch  straight  pipe,  one  end  of  which  was  screwed 
into  the  test  head  of  the  experimental  tube,  while  the  other  end 
passed  through  the  end  of  the  hydraulic  test  cylinder  to  the  external 
atmosphere.  A joint  stanch  against  fluid  pressure  was  main- 
tained by  means  of  the  cupped  leather  ring  packing  shown. 

For  the  other  two  styles  of  heads,  where  the  experimental  tube 
was  not  necessarily  kept  central  in  the  hydraulic  test  cylinder,  the 
flexible  vent  pipe,  made  by  coiling  a sufficient  length  of  ^-inch  gas 
pipe  into  a helical  form,  was  used. 

Autographic  Calipering  Apparatus. 

Since  it  was  anticipated  that  the  out-of-roundness  of  the  tube 
under  test  would  exert  a controlling  influence  on  its  behavior,  it 
was  thought  best  to  devise  a piece  of  apparatus  that  would  indi- 
cate this  deviation  from  perfect  roundness  with  accuracy  and  ex- 
pedition. A number  of  schemes  for  accomplishing  this  result 
were  worked  out.  Of  these  two  were  constructed  and  used,  known 
respectively  as  No.  1 and  No.  2. 

Autographic  Calipering  Apparatus  No.  2 was  used  in  calipering 
the  bulk  of  the  tubes  placed  under  test,  and  gave  most  satisfactory 
results.  It  was  preceded  by  Autographic  Apparatus  No.  1,  of 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


£ 


Fig.  6. — Sketch  Showing  the  Principle  of  Action  of  Autographic  Calipering 

Apparatus  No.  2. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  21 


Fig.  7. — Autographic  Calipering  Apparatus  No.  2.  Especially  Designed  and  Con_ 
' STRUCTED  FOR  OBTAINING  THE  OuT-0 F-ROUNDNESS  OF  TUBES  USED  IN  MaKINq 

Collapsing  Tests  Conducted  by  Prof.  R.  T.  Stewart. 


22  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

much  lighter  weight,  constructed  on  a somewhat  different  prin- 
ciple. This  apparatus  proved  too  flimsy  for  the  service  required 
of  it,  and  was  replaced  by  No.  2 apparatus. 

Calipering  Apparatus  No.  2. — The  construction  of  autographic 
apparatus  No.  2 is  clearly  shown  in  Fig.  7,  some  of  the  minor 
details  being  omitted  in  order  to  make  the  drawing  show  more 
clearly  the  main  features  of  the  apparatus ; the  cord  for  communi- 
cating motion  from  the  tube  under  test  to  the  recording  drum, 
together  with  the  necessary  weights  and  carrying  pulleys,  being 
omitted.  These  are  shown  in  Fig.  6,  which  is  a diagrammatic 
form  of  the  apparatus  that  shows  clearly  the  principle  of  action. 

The  tube  being  calipered  is  made  to  rotate  by  any  suitable  means 
on  supporting  guide  wheels,  one  pair  of  which  are  shown  at  EE. 
The  frame  BBB,  by  means  of  the  guides  FF  and  the  counterbal- 
ancing lever  and  weight  G,  keeps  the  lower  calipering  point  at- 
tached to  it  constantly  in  contact  with  the  under  surface  of  the  tube 
while  it  is  being  made  to  rotate.  It  is  evident  that  any  variation  in 
the  length  of  the  vertical  diameter  of  the  tube  while  rotating  will 
cause  a motion  of  the  upper  calipering  point  C with  respect  to  the 
frame  BBB,  which  variation  is  magnified  tenfold  by  the  lever  A 
and  then  recorded  on  a sheet  of  paper  wrapped  about  the  record 
drum  D.  Motion  is  communicated  from  the  tube  T to  the  record 
drum  D by  means  of  a cord  weighted  at  both  ends,  in  order  to  pre- 
vent slipping,  the  cord  being  made  to  pass  once  around  both  the 
tube  and  the  pulley  P attached  to  the  record  drum  D.  In  this  way 
the  tube  being  calipered  and  the  record  drum  are  made  to  rotate 
synchronously. 

To  the  right  are  shown  two  cards  taken  from  the  record  drum. 
On  these  cards  the  line  XX  is  a reference  line,  similar  to  the 
atmospheric  line  on  an  engine  indicator  card.  It  is  drawn  by 
rotating  the  record  drum  by  hand  while  a distance  piece  is  placed 
between  the  calipering  points,  the  length  of  this  distance  piece 
being  made  equal  to  the  nominal  outside  diameter  of  the  tube  being 
calipered.  The  result,  of  course,  is  a horizontal  straight  line. 
The  line  YY  is  produced  by  rotating  the  tube  between  the  caliper- 
ing points  in  the  manner  described  above.  The  distances  between 
these  two  lines  show,  then,  to  a tenfold  scale,  the  variation  of  the 
actual  diameters  from  the  nominal  diameter  for  any  given  cross- 
section. 

Figs.  8-10  show,  to  a reduced  scale,  representative  examples 
selected  from  the  numerous  autographic  records  made  in  connec- 


Fig.  8. 


Fig.  9. 


Fig.  10 


2 f>  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


tion  with  this  research  on  the  collapsing  pressures  of  tubes.  Al- 
together about  6,000  of  these  autographic  records  have  been  made 
and  are  on  file. 


Collapsing  Tests,  Series  One,  Showing  the  Influence  of 
Length  of  Tube  on  the  Collapsing  Pressure. 

Since  the  influence  of  the  length  of  tube,  between  transverse 
joints  or  end  connections  tending  to  hold  it  to  a circular  form, 
upon  the  collapsing  pressure  appeared  to  be  the  most  uncertain 
element  entering  the  problem,  it  was  thought  best,  first  of  all,  to 
determine  the  precise  nature  of  this  influence.  Accordingly,  it 
was  decided  to  make  a series  of  tests  on  a single  diameter  of  tube 
for  all  the  commercial  thicknesses  of  wall  obtainable,  in  five  dif- 
ferent lengths  of  from  2J  to  20  feet. 

Selection  of  Tubes  for  Testing. — The  tubes  used  in  making  this 
series  of  tests,  as  well  as  the  other  series  contained  in  this  paper, 
were  obtained  from  the  National  Department  of  the  National  Tube 
Company,  McKeesport,  Pa.,  on  order  issued  by  the  Job  Work 
Shop,  in  the  usual  commercial  way.  Those  who  filled  these  orders 
had  no  means  of  knowing  for  what  purpose  the  tubes  were  to  be 
used,  and  presumably,  therefore,  the  tubes  thus  obtained  for  pur- 
poses of  testing  represent  fair  samples  of  the  regular  commercial 
product  of  the  mills. 

Every  tube  thus  obtained,  without  exception,  was  tested,  the 
complete  results  of  all  tests  being  recorded  in  the  Log,  a summary 
of  which  appears  in  this  paper.  The  results  may  therefore  be 
accepted  as  indicating  the  strength  to  resist  fluid  collapsing  pres- 
sures of  this  Company’s  Bessemer  steel  lap-welded  tubes,  the 
tubes  being  taken  just  as  they  are  found  in  stock. 

Diameter  of  Tube  Tested. — For  Series  One  it  was  decided  to 
use  8J-inch  well  casing,  which  has  a nominal  outside  diameter  of 
8f  inches.  This  size  was  adopted  because,  taking  all  things  into 
consideration,  it  seemed  to  afford  the  greatest  opportunities  for 
getting  at  the  results  desired. 

The  various  diameters  of  the  individual  tubes  of  this  series  are 
given  in  columns  2,  3,  4,  5 and  34  of  the  tabular  statement  of 
principle  results  of  tests,  Figs.  11-15.  (See  folders.) 

The  nominal  outside  diameter , in  inches,  appears  in  column  2, 
and  is  for  this  series  8.625  inches  for  all  tubes  tested. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


The  average  outside  diameter,  as  made  up  from  measurements 
on  each  individual  tube,  at  intervals  of  one  foot  along  its  entire 
length,  are  entered  in  column  3.  These  measurements  were  made 
by  means  of  an  especially  constructed  steel  tape,  the  spacing  of 
whose  graduations  bore  the  same  relation  to  those  of  an  ordinary 
scale  divided  into  inches  and  hundredths  as  the  length  of  the  cir- 
cumference of  a circle  bears  to  its  diameter.  That  is  to  say,  each 
inch  division  on  the  tape  was  actually  3.1416  inches  long.  By  this 
means  diameters  could  be  read  directly  from  circumferential  meas- 
urements, thus  making  it  possible,  by  means  of  a single  reading, 
to  obtain  an  average  of  all  the  different  diameters  at  any  particular 
foot  length  of  the  tube.  The  advantage  of  this  method  will  be 
appreciated  when  it  is  remembered  that  more  than  5,000  deter- 
minations of  mean  diameters,  at  the  different  cross-sections,  one 
foot  apart,  had  to  be  made  for  Series  One  and  Two  of  this  investi- 
gation alone,  the  tubes  tested  in  every  case  not  being  perfectly 
round  at  any  of  these  sections. 

The  greatest  and  least  outside  diameters,  at  the  place  of  collapse, 
by  which  is  meant  that  point  of  the  length  of  tube  where,  after 
failure,  the  distortion  was  greatest  (see  Fig.  16,  page  30),  are  en- 
tered respectively  in  columns  4 and  5. 

These  entries  were  made  up  from  the  measurements  made  for 
out-of -roundness  of  tube,  at  each  foot  along  its  length,  before  being 
placed  in  the  hydraulic  test  cylinder. 

Thickness  of  Wall. — There  were  five  nominal  thicknesses  of  wall 
tested  in  Series  One,  namely:  0.180,  0.229,  0.271,  0.281,  and 
0.322-inch,  having  nominal  weights  of  respectively  16.07,  20.10, 
24.38,  25.00  and  28.18  pounds  per  foot  length  for  the  outside 
diameter  of  8f  inches  chosen  for  this  series.  The  actual  plain- 
end  weights  per  foot  corresponding  to  these  nominal  thicknesses 
were  respectively  16.23,  20.53,  24.18,  25.04,  and  28.55  pounds. 
The  nominal  thicknesses  of  wall  of  the  different  tubes  tested 
appear  in  column  6 and  the  corresponding  nominal  weights  in 
columns  13  and  34. 

The  average  thickness  of  wall  of  the  tubes  of  this  series  appears 
in  column  7.  This  average  thickness  for  each  tube  was  calculated 
from  the  plain-end  weight,  length,  and  average  outside  diameter, 
as  given  in  column  3.  In  this  way  a more  exact  value  could  be 
arrived  at  for  the  average  thickness  than  by  any  other  practical 
means. 


28  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

The  greatest  and  least  thickness  of  wall  at  the  place  of  collapse 
are  given  respectively  in  columns  8 and  9.  These  were  obtained 
from  the  tube,  after  collapse,  by  cutting  it  across  at  the  point  of 
its  length  where  the  distortion  appeared  to  be  greatest,  after  which 
the  greatest  and  least  thicknesses  were  measured  by  means  of  a 
micrometer  caliper. 

Weights  of  Tubes. — The  nominal  weights,  in  pounds  per  foot 
length,  of  the  tubes  tested  are  given  in  columns  13  and  34.  For 
this  series,  having  the  uniform  nominal  outside  diameter  of  8f 
inches,  these  nominal  weights  were  16.07,  20.10,  24.38,  25.00  and 
28.18  pounds  per  foot  length.  The  actual  plain-end  weights  cor- 
responding to  the  nominal  thicknesses  of  wall  were  respectively 
16.23,  20.53,  24.18,  25.04,  and  28.55  pounds  per  foot. 

The  actual  plain  end  weights  per  foot  length  of  the  individual 
tubes  tested  are  entered  in  column  14.  The  entries  in  this  column 
were  made  up  by  dividing  the  weight  in  pounds  of  each  tube  by  its 
length  in  feet,  as  given  in  column  11.  The  weighing  was  done  on 
a tested  platform  scale,  and,  for  those  tubes  that  were  threaded 
before  weighing,  an  allowance  was  applied  for  the  loss  of  weight 
due  to  threading,  this  allowance  being  arrived  at  experimentally 
by  weighing  a number  of  pieces  both  before  and  after  threading. 
In  this  way  the  corrections  for  the  different  styles  of  thread  were 
arrived  at. 

Lengths  of  Tubes . — The  tubes  for  Series  One  were  ordered  in 
five  lengths  for  each  of  the  five  thicknesses  tested.  These  lengths 
are  entered  in  column  10,  and  were  20,  15,  10,  5,  and  2^  feet, 
including  the  threaded  ends,  for  this  series.  For  the  tubes  of  all 
the  other  series  contained  in  this  report  the  length  ordered  in  each 
case  was  20  feet,  for  both  plain  and  threaded  ends.  It  will  be 
noted  that  the  groups  'Nos.  26  to  34  inclusive,  and  77  to  79  in- 
clusive, were  supplied  in  random  lengths,  presumably,  because 
the  stock  did  not  contain  tubes  of  sufficient  length,  at  that  date, 
to  fill  the  order  in  20-foot  lengths  for  tubes  of  these  particular 
weights.  All  the  other  tubes  were  supplied  in  substantially  the 
lengths  as  ordered. 

The  actual  lengths  of  the  tubes  tested,  to  the  nearest  thousandth 
of  a foot,  as  measured  by  means  of  a steel  tape,  are  entered  in 
column  11.  These  measurements  for  this  series  include  both 
threaded  ends,  the  coupling  that  is  usually  shipped  as  a part  of  every 
threaded  tube,  and  which  is  ordinarily  measured  up  as  a part  of  its 
length,  not  being  included  in  these  measurements.  The  measure- 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  29 

ments  on  the  tubes  of  the  other  series  that  have  threaded  ends  were 
made  in  the  same  manner. 

The  unsupported  lengths  of  the  tubes  are  entered  in  column  12. 
These  were  arrived  at  by  subtracting  the  lengths  of  the  portions  of 
the  threaded  ends  that  lay  inside  the  couplings  from  the  corre- 
sponding actual  lengths  as  given  in  column  11.  Column  12  then 
shows  the  actual  length  of  tube  exposed  to  a fluid  collapsing  pres- 
sure, and  which,  at  the  same  time,  received  no  direct  supporting 
action  from  any  outside  source  tending  to  hold  it  to  a circular 
form.  These  were  the  lengths  used  in  deducing  the  general  con- 
clusions from  the  individual  experiments,  as  shown  in  Fig.  21. 

Collapsing  Pressure . — In  and  near  the  region  of  expected  col- 
lapse the  hydraulic  pressure  within  the  test  cylinder  and  surround- 
ing the  tube  under  test  was  increased  at  the  rate,  in  pounds  per 
second,  shown  in  column  17.  This  rate  in  every  case  was  low 
enough  to  permit  of  making  accurate  readings  of  the  fluid  pressure 
exerted  upon  the  tube  under  test,  and  also  allow  for  free  elastic 
deformation  of  the  material  constituting  the  walls  of  the  tubes. 
In  no  case  was  the  elastic  limit  of  the  material  exceeded  until  after 
failure  had  actually  occurred.  The  apparent  stress  on  the  wall 
of  the  tube  at  instant  of  failure  ranged  from  about  7,000  to  31,000 
pounds  per  square  inch,  respectively,  for  the  relatively  thinnest 
and  thickest  walls  in  Series  Two.  (See  page  73  and  Fig.  51.) 

The  fluid  collapsing  pressure , in  pounds  per  square  inch,  are 
entered  in  column  15,  the  gauge  from  which  the  pressure  was 
read  being  indicated  opposite  in  column  16,  where  B,  C and  D 
designate  respectively  the  1,000,  3,000  and  8,500  pounds  capacity 
Shaw  differential-piston  mercury  gauges.  These  gauges  were  fre- 
quently compared,  and  the  slight  differences  were  adjusted  so  as 
to  make  the  readings  on  B and  D conform  to  those  on  C,  the 
intention  being  to  have  gauge  C calibrated  after  completion  of 
the  tests. 

Collapsed  Portion. — The  appearance  of  the  tube  after  being  col- 
lapsed in  the  hydraulic  apparatus  is  clearly  shown  by  the  photo- 
graphs and  by  the  collapsed  sections,  examples  of  which  are 
shown  in  Figs.  16  and  17. 

These  photographs  of  collapsed  tubes , taken  in  conjunction  with 
the  collapse  sections,  show  very  clearly  the  precise  nature  of  the 
distortion  resulting  from  the  subjection  of  the  tube  to  an  external 
fluid  pressure  sufficient  to  cause  failure.  Referring  to  Fig.  16, 
which  is  a reproduction  of  the  photograph  of  Nos.  50  to  54  in- 


30  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  16.— Photograph  of  Tubes,  Nos.  50  to  54,  after  being  Collapsed. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  31 


32  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

elusive,  it  will  be  observed  that  two  views  of  each  tube  are  shown. 
One  of  these  was  taken  looking  in  the  direction  of  the  axis  of  col- 
lapse, while  the  other  view  was  taken  after  the  tubes  were  rotated 
on  their  supports  through  an  angle  of  90  degrees. 

These  tubes  were  all  calipered  for  out-of -roundness,  at  distances 
of  one  foot  apart  along  their  entire  lengths,  before  being  placed 
in  the  hydraulic  test  apparatus,  and,  while  doing  this,  the  ends 
of  the  greatest  and  least  diameters  at  each  of  these  sections  were 
marked  on  the  tube  by  means  of  plus  (+)  and  minus  ( — ) signs, 
as  shown  on  these  photographs.  Where  noughts  (0)  appear  the 
tube  was  so  nearly  round  as  to  make  it  difficult  to  distinguish 
a greatest  and  least  diameter  at  that  section,  even  with  the  ex- 
ceedingly refined  methods  in  use  for  making  this  determination. 

The  length  of  collapsed  portion  of  tube,  in  feet,  is  entered  in 
column  18.  This  length  was  determined,  after  collapse,  by  meas- 
uring the  length  of  the  portion  of  the  tube  which  showed  a per- 
manent distortion — for  example,  referring  to  Fig.  16,  test  num- 
ber 54,  it  appears  that  this  permanent  distortion  just  becomes 
measurable  at  4£  feet,  is  greatest  at  7\  feet,  and  terminates 
at  10^  feet.  In  this  case,  then,  the  length  of  collapsed  portion  is 
6 feet,  which  is  somewhat  less  than  one-third  the  length  of  the 
tube.  More  than  two-thirds  of  the  length  of  this  tube  has  suf- 
fered no  permanent  distortion  whatever.  This  localization  of 
collapsed  region  is  typical  of  all  tubes  tested  in  relatively  long 
lengths. 

The  lengths  of  the  collapsed  portions  expressed  in  diameters 
of  the  tubes  were  obtained  by  dividing  the  length  of  collapsed 
portion  of  each  tube  by  its  outside  diameter,  both  being  expressed 
in  inches. 

The  distance  of  collapsed  portion  from  the  end  of  tube , column 
20,  was  obtained  by  measuring  the  distance  from  the  point  of 
greatest  distortion — for  example,  at  7\  feet  for  test  number  54, 
Fig.  16,  to  the  numbered  end  of  tube,  as  shown  in  the  photographs. 
For  further  discussion  of  this  matter  see  page  75. 

The  angular  distance  from  weld , column  21,  was  obtained  by 
measuring  the  angular  distance  from  the  axis  of  collapse  (see 
Fig.  17)  to  the  weld.  Assuming  that  the  observer  is  stationed  at 
the  numbered  end  of  the  tube,  and  looking  in  the  direction  of 
its  length,  angles  measured  in  the  direction  in  which  the  hands  of 
a clock  rotate  are  marked  plus  ( -f-  ),  while  those  measured  in  the 
opposite  direction  are  marked  minus  ( — ) . 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  33 

These  angular  distances  were  measured  by  means  of  an  espe- 
cially constructed  tape.  On  this  tape  distances  were  laid  off  equal 
to  the  circumference  of  the  different  sizes  of  tubes  to  be  tested. 
These  distances  were  then  divided  into  360  equal  parts,  each  of 
which  would  represent  the  length  of  one  degree  of  arc  of  the  cir- 
cumference of  the  tube.  It  is  evident  that  a tape  constructed  after 
this  mannner  affords  a most  satisfactory  means  for  measuring  an- 
gular distances  around  tubes.  In  this  way  the  original  angular 
distance  between  two  points  on  the  surface  of  a tube,  lying  in  the 
same  transverse  plane,  can  be  measured  just  as  readily  after  the 
tube  has  been  distorted  as  before.  When  it  is  considered  that  all 
of  these  measurements  for  angular  distance  from  axis  of  collapse 
to  the  weld  had  to  be  made  at  the  place  of  greatest  distortion,  after 
collapse  had  taken  place,  the  utility  of  this  special  tape  will  be 
apparent. 

Physical  Properties  of  the  Steel. — The  physical  properties  en- 
tered in  columns  22  to  25,  inclusive,  are  the  averages  from  three 
test  specimens  cut  from  each  tube,  after  removal  from  the  hy- 
draulic test  apparatus,  the  test  specimens  in  every  case  being  cut 
from  the  undistorted  portion,  except  for  the  cases,  clearly  noted 
in  the  tabular  statement  of  Series  Two,  where  these  specimens 
were  cut  from  the  distorted  portion.  Tor  these  latter  it  will 
be  observed  that  the  yield  point  is  raised  and  at  the  same  time 
the  elongation  and  reduction  of  area  are  lowered,  more  or  less 
according  as  the  portion  from  which  the  specimens  were  cut 
were  more  or  less  distorted.  In  working  up  the  result  for  this 
paper  it  was  assumed  that  the  material  of  these  tubes  possessed 
the  same  average  physical  properties  as  the  others  of  the  same 
series.  This  seemed  but  a fair  assumption  to  make  under  the  cir- 
cumstances, since  there  was  no  apparent  reason  why  the  material 
constituting  them  should  differ  in  respect  to  physical  properties 
from  that  of  the  other  tubes  tested  at  the  same  time. 

All  the  specimens  for  the  physical  tests  were  cut  lengthwise  of 
the  tube  and  were  pulled  in  the  testing  machine  without  being 
previously  subjected  to  any  straightening  action  whatever.  The 
test  specimens  were  substantially  of  the  form  and  dimensions 
as  that  adopted  for  plate  metal  by  the  American  Section  of  the 
International  Association  for  Testing  Materials,  namely:  eight 
inches  between  extreme  gauge  marks,  one  and  one-half  inches  wide 
throughout  the  gauged  portion,  and  enlarged  to  two  inches  width 
at  the  ends  where  held  in  the  grip  of  the  testing  machine. 


34  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

The  physical  tests  were  made  at  the  National  Tube  Company’s 
Laboratory,  McKeesport,  Pa.,  under  the  immediate  direction  of 
their  metallurgist,  Mr.  G.  M.  Goodspeed. 

Chemical  Analysis. — The  chemical  analyses,  columns  26  to  31 
inclusive,  were  also  made  at  the  Tube  Company’s  Laboratory,  from 
drillings  taken  from  the  tube  or  from  the  ends  of  the  physical 
test  specimens.  m 

Material. — The  kind  of  material,  whether  Bessemer  steel,  open- 
hearth  steel,  or  wrought  iron,  constituting  the  different  experi- 
mental tubes,  as  entered  in  column  32,  was  determined  for  each 
case  by  means  of  the  chemical  analysis. 

It  will  be  observed  that  the  experimental  tubes,  with  but  few 
exceptions,  were  composed  of  Bessemer  steel.  In  Series  One,  three 
of  the  tubes  tested  proved  to  be  wrought  iron  and  also  three  open- 
hearth  steel,  all  the  others  of  this  series  being  Bessemer  steel.  In 
Series  Two,  one  group  of  five  tubes  proved  to  be  wrought  iron. 

The  Bessemer  steel  constituting  the  tubes  had  the  following 
average  physical  properties: 


Tensile  strength,  pounds  per  sq.  inch 58,000 

Yield  point 37,000 

Elongation  in  8 inches,  per  cent 22 

Reduction  of  area,  per  cent 57 


And  the  following  average  chemical  analysis : 


Sulphur,  per  cent 069 

Phosphorus,  per  cent 106 

Manganese,  “ “ 35 

Carbon,  “ “ 074 


Deduction  of  Law  Showing  the  Relation  of  Collapsing 
Pressure  to  the  Length  of  Tube. 

Regrouping  of  Tests. — In  order  to  arrive  at  the  law  expressing 
the  collapsing  pressures  of  Series  One  in  terms  of  the  length  of 
tube  and  the  different  thicknesses  of  wall,  for  the  diameter  chosen, 
it  was  necessary,,  first  of  all,  to  arrange  the  tests  of  this  series  in 
the  manner  shown  in  the  table,  Pigs.  18-20.  In  this  table  all 
the  values  entered  in  the  different  columns,  except  the  last  three 
of  the  group  of  four  columns  headed  “ Collapsing  Pressure,”  are 
taken  directly  from  the  corresponding  columns  of  the  table  of 
“ Principal  Results  of  Collapsing  Tests,  Series  One,”  Pigs.  11-15. 

It  will  be  observed  that  the  tests  have  been  regrouped  so  that, 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


35 


EFFECT  OF  LENGTH  ON  COLLAPSING  PRESSURE. — Abstract  from  Logof 
Tests  Conducted  by  Prof.  R.T.Stewart, /50Z-0+,  on  National  Tube  Co/s  Lap- 
welded  Bessemer  Steel  Tubes  in  Lenqths  of  2'k,5,IO,lS,andZO  Feet,?  %"  Outside 
Diameter, to  Determine  the.  Effect  of  Length  of  Tube  on  the  Collapsing  Pressure; 
to  which  is  Added  a Comparison  with  Values  Read  from  the  Curve.  M,  Represent- 
ing the  Average  Results  of  these  Tests.  Mode  by  e.e.s.  under  direction  of  a.  r s.  /9os. 


rests  Grouped  and  Arranged  in  Order  of  Length  and  Thickness  of  Tube. 


Actual 

Thickness  of  Wall, 

Unsupported 

Actual 

Collapsing 

Pressure 

Designation  of  Tube, 

Number 

Outside 

Inc 

hes. 

Length 

Plain  End 

Pour, 

c/s  per 

Sguare  Inch. 

of  Test. 

Diameter, 

Nominal 

Computed 

of  Tube. 

Weight, 

Observed 

Corrected  to 

From 

% Vo  not/ on 

cts  Reported. 

Inches. 

from  W9f 

feet. 

Lbs. per  Ft. 

Nom.  Thk. 

Curve  FI. 

from  M. 

zz 

8.057 

0.108 

2.213 

15.23 

8/5 

990 

- 3 

29 

8.0S5 

0.170 

2.2/2 

IS.NI 

1085 

1/85 

12  2 

2/xPoet  Lengths. 

23 

8. CNN 

0.180 

0.181 

2.220 

I0.NI 

1685 

/d  75 

no 

+// 

8 '/j,‘ Casing,  10.07  lbs. 

25 

8.00! 

0.181 

2.205 

I0.N3 

985 

905 

- 0.5 

2/ 

8.058 

6.182 

2.198 

/ 6.N5 

9/5 

895 

- 7.5 

Average, 

8.050 

0.170 

2.2(0 

15.99 

977 

101 2 

t N.N 

’ /9 

8.005 

O.S73 

N.  7/8 

/5.0N 

525 

005 

t 6 

/r 

8.601 

0.180 

N.702 

/ 0.3N 

5N0 

SNO 

- 5 

5 Foot  Lengths. 

n 

8.059 

0.180 

6.181 

N.  768 

/0.N2 

575 

SOS 

570 

- / 

u 

8.050 

6.182 

N.08% 

/0.N3 

6/5 

590 

t 3.5 

8 '/jf  Casing,  16.07  lbs. 

20 

8.05N 

6.182 

N.763 

/0.N3 

705 

085 

tzo 

Average 

8.058 

0.186 

N.70N 

10.25 

592 

597 

t N.7 

/9 

8.  CNN 

0.171 

9.095 

15.5 / 

N55 

S55 

t 6 

IS 

8.006 

0.177 

9.09  S 

10.03 

590 

025 

i/9 

/ 0 Foot  Lengths. 

is 

8.05/ 

0.180 

0.178 

9.  765 

IC.II 

550 

575 

525 

t 9.5 

!Z 

8.05N 

0.180 

9.09 1 

10.26 

570 

570 

t 8.5 

V'/tf  Casing,  10.07  lbs. 

II 

8.002 

0./8N 

9.7/5 

10.05 

575 

535 

t 2 

30 

8.070. 

0.229 

0.197 

11.950 

/ 7. 79 

050 

NOS 

520 

-10.5 

8'/h  Casing,  20. to  lbs. 

/W«ra,« 

8.059 

0.181 

/ 0.075 

10.39 

505 

559 

t S7 

7 

8.05/ 

0.I7N 

IN. 7 23 

15.76 

N25 

N90 

- 2 

•? 

8.055 

0.183 

IN.  7 62 

/ 0.5N 

550 

520 

t N 

IS  Foot  Lengths. 

C 

8.051 

0.190 

6.180 

IN.708 

/ 0.8  2 

575 

510 

500 

t 2 

10 

8.052 

6.188 

IN.  700 

10.95 

S80 

995 

- / 

8 ’/jy" Casing,  16.07  Uos. 

9 

8.  OSS 

6.19/ 

IN.  768 

17.21 

010 

995 

- / 

Ave rage 

8.053 

0. 189 

IN. 7 68 

10.00 

sm 

502 

+ 0,9 

/ 

8.057 

0./70 

19.818 

15.92 

N50 

990 

t 3 

9 

8.0NO 

6. 183 

19.762 

/C.SN 

N50 

920 

N75 

-U.5 

20  Foot  Lengths. 

3 

8.CNI 

0.120 

6.  no 

19.095 

/ 0.77 

535 

9 75 

0 

S%"  Casing,  16.07  tbs. 

Z 

8.03  7 

0.191 

19.0  90 

17.2  N 

025 

5/5 

f 2S 

S 

8.038 

6.191 

19.769 

/ 7. 23 

02  0 

505 

t O.S 

Average 

8.CN3 

0.185 

19.72  N 

U.7 9 

530 

981 

+ /.3 

NS 

8.050 

0.2/0 

2.188 

18.93 

I2N0 

1935 

- / 

N2 

8.077 

6.2/0 

2 .200 

19.02 

1353 

/ 595 

1950 

t 0.5 

2 Zz  Foot  Lengths. 

V? 

8.055 

0.229 

0.2/2 

2.2/8 

19.10 

/30S 

198  0 

t z 

NO 

8.0N8 

0.2/3 

2.220 

19.18 

1330 

1995 

+ 3 

VZyCasinq,  20. /0  lbs. 

97 

8.057 

0.2  IN 

2,193 

19.20 

I3N0 

1995 

t 3 

8.6S7 

0.2/2 

2.265 

19.10 

13/N 

i*no 

t 2.7 

NN 

8.  UN 

0.207 

N.7II 

18.00 

910 

1/05 

f Z 

9/ 

8.053 

0.208 

9.080 

/8.7N 

97  0 

1215 

t 6 

S Foot  Lengths. 

92 

8.670 

0.2  29 

0.2/0 

N.087 

18.93 

80S 

1030 

UN  5 

-/o 

V/ii Casing,  20.10  lbs. 

NO 

8.657 

0.210 

N.  7/3 

/ 9.N8 

975 

1125 

- z 

N3 

8.00/ 

6.2/9 

N.080 

19.72 

875 

995 

-13 

Average 

8.00/ 

0.2.12 

N.C95 

19. // 

90  7 

1100 

- 3.N 

38 

8.000 

0.268 

9.7/6 

18.77 

7 00 

930 

/07S 

-/  3.S 

32 

8.000 

6.20  9 

l/.NSI 

18.86 

73  0 

956 

toss 

-•0 

31 

8.058 

0.2/0 

n.8/0 

18.90 

8/0 

/ 020 

1050 

- 3 

35 

8.005 

6.2/2 

9.701 

19.  n 

886 

107 0 

/07S 

- 0.5 

!0  Foot  Lengths 

30 

8.003 

0.229 

0.2  IS 

9.702 

/9.3V 

8NZ 

1000 

" 

- 7. 

39 

8.088 

0.217 

9.705 

19.59 

895 

920 

" 

- 9 

9/f“Ca si ng,  ZO./O  lbs. 

37 

8.005 

0.220 

9. 7 6/ 

19.82 

9C0 

/600 

" 

- /.5 

33 

8.0  ON 

0.220 

II.3LN 

20.38 

8N0 

875 

/OSS 

- / 7 

39 

8.009 

0.232 

11.300 

20.89 

900 

925 

“ 

- IZ5 

8.006 

0.2/7 

10.502 

19.51 

89 1 

979 

-8T.Z 

! 2 3 4 5 6 7 8 9/0 


Fig.  18, 


36  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


EFFECT  OF  LENGTH  ON  COLLAPSING  PRESSURE. Abstract  from  Log  of 

Tests  Conducted  by  Prof.  R.T.Stewart,  1902-04,  on  National  Tube  Co.’s.  Lap- 
welded  Bessemer  Steel  Tubes  in  Lengths  of  Z'/x,5,IO,l5,and20  Feet^Vs'Outside, 
Diameter ; to  Determine  the  Effect  of  Length  of  Tube  on  the  Collapsing  Pressure-, 
to  which  is  Added  a Comparison  with  Values  Read  from  the  Curve,  M, Represent- 
ing the  Average  Results  of  these  Tests.  node  by  e.e.  s.under  direction  of  n.r.s.,  isos. 


rests  Grouped  on  d 4 rranqad  in  Order  of  Langth  arid  Thick  ness  of  Tube.. 


Number 

of  Test. 

Actual 

Outside 

Diameter. 

Inches. 

Thickness  of  Wall, 
Inches. 

Unsupported 

Length 

Feet. 

Actual 
Plain  End 
V/eight, 
Lbs. per  Ft. 

Collapsing 
Pounds  per 

Pressure,. 
Square  Inch. 

Designation  of  Tube, 
as  Report e d. 

Nominal 

Computed 
from  Wgf. 

Observed 

Corrected  to 

Nom.  Thk. 

Fro  no 
Curve  M. 

% Variation 
from  M. 

29 

5.659 

0.2/3 

12.636 

n.23 

150 

10/5 

- 25 

29 

9.6  50 

0.229 

0.2/3 

12.372 

19.1 6 

7 SO 

115 

!0  80 

-12.5 

!5  Foot  Lengths. 

27 

9.629 

0.233 

13.373 

20.15 

ms 

/ 075 

- 9 

I'/j/"  Casing  , 20.10 /bs. 

A verage 

9.696 

0.220 

12.792 

H.79 

90S 

1 0 02 

- 6.3 

20  Foot  Lengths 

26 

9.609 

0.229 

0.2/9 

19.966 

19.57 

no 

170 

910 

- / 

15v"Cq si nq , Zo./O/hs. 

70 

9.673 

0.27 1 

0.253 

2.197 

22.72 

1975 

/ (75 

- / 3.5 

r'/q  Casing,  2 H.3* lbs. 

93 

9.65J 

0.22/ 

0.259 

2 .156 

23.23 

ms 

2/ 25 

/// 

If"  Lind  Pipe, ZS. 00  tbs. 

97 

2.675 

0.21/ 

6.2  6/ 

2./SI 

23.95 

11/5 

2030 

1 12 

U ..  ..  it  *f 

16 

9.656 

0.Z9I 

0.261 

2/96 

29.00 

1190 

19  75 

t 2 

/#  » /*  n «i 

73 

1.690 

0.27/ 

0.269 

2.136 

29.15 

1150 

19  70 

/93S 

- 3 

C asin  g ,2*.3S  lbs. 

7/ 

9.650 

0.27/ 

0.27/ 

2.196 

29.20 

1930 

1930 

0 

ft  H II  » 

72 

9.662 

0.27/ 

0.273 

2.626 

29.97 

mo 

/1 55 

- 5 

.1  M «l  M 

79 

1.699 

0.271 

0.279 

2 .196 

19.50 

/71S 

1750 

- 9.5 

*«  M II  M 

9S 

9.699 

0.211 

0.2  71 

2.159 

29.92 

1765 

/(IS 

-/3 

Line  Pipe,  25. JO  lbs. 

19 

9.639 

0.291 

0.279 

2.196 

29.10 

2200 

2/10 

t 1.5 

Z'/zFoot  Lengths. 

Average 

9.659 

0.269 

2.135 

29.09 

/172 

noo 

- 1.0 

Corrected  to  Nom. Thk $.27/ 

as 

9. 69  9 

0.27/ 

0.257 

9.631 

22.91 

1395 

IS/  0 

- 9 

X'/q"  Casing,  2 *.3?  lbs. 

cc 

9.653 

0.27  / 

0.261 

9.(9/ 

23.17 

1520 

15(0 

- 6 

0 ••  .1  ii 

£9 

1.670 

0.271 

0.261 

9.651 

29.02 

7725 

IKS 

+ r 

II  1.  H || 

6 7 

9.65/ 

0.271 

0.269 

9.69/ 

29.07 

1690 

1670 

t 0.5 

II  M I.  |» 

92 

9.679 

0.21/ 

0.2  73 

9.696 

2 9.50 

2030 

zoos 

/(6S 

t2l 

IT  Line  Pipe,Zs.fO 1 bs. 

9! 

9.669 

0.211 

0.275 

9.(99 

2 9.6/ 

1(25 

/ 570 

- 5.5 

i«  i.  i.  i.  i. 

£5 

9.656 

0.271 

0.277 

9.626 

29. 16 

/ 750 

1695 

/ / 

TfVii  Casing , 2V.3*  lbs. 

11 

1.65! 

0.211 

0.279 

9.69/ 

29.13 

1615 

1525 

- 1.5 

T"  Line  Pipe,  2S./0  lbs. 

90 

9.615 

0.21 1 

0.219 

9.(96 

25.95 

noo 

1556 

- 7 

ii  ii  ii  i.  ii 

99 

1.699 

0.21/ 

0.217 

9.(36 

25.75 

/ 615 

/915 

-to 

5 Foot  Lengths 

Average 

9.669 

0.279 

9.691 

2 9.5/ 

/ 619 

1653 

- /.5 

Corrected  to  Nom.Th  k.0.21 1. 

15 

1.669 

0.21/ 

0.260 

9.696 

23.2/ 

/ 575 

1615 

*■  9.5 

V" Line  Pipe , ZS./O  lbs. 

69 

9.657 

0.27/ 

0.260 

9.666 

23.2/ 

/950 

/ 570 

t /S 

V'/S  Casing  , ZH.sv/hs. 

a 

9.669 

0.2  7/ 

0.265 

9.656 

23.7  5 

//SO 

1215 

-21.5 

I#  #.  ii 

63 

9.662 

0.2  7/ 

0.267 

9.69/ 

23.19 

1595 

/625 

t s 

ii  ii  //  // 

62 

1.679 

0.27/ 

0.261 

9.636 

29.05 

1621 

1660 

t 7 

ii  • ii  /i  // 

S3 

9.669 

0.211 

0.270 

9.(51 

29.20 

1990 

/9S0 

1550 

- (.5 

T "Line  Pipe , ZS.  to  lbs. 

97 

1.669 

0.211 

0.272 

9.(56 

29.90 

/ 695 

1635 

t S.S 

n o,  a ii  ii 

*9 

9.695 

0.21/ 

0.275 

9.699 

29.72 

/500 

I960 

- 6 

ii  ii  /i  ii  ii 

60 

2.673 

0.2  7/ 

0.276 

9.596 

29.75 

1950 

/ 795 

t/6 

9'/S  Casing  , ZN.39  lbs. 

S <6 

1.663 

0. 21/ 

0.271 

9.(36 

29.95 

/S95 

/970 

- 5 

**  Line  Pipe,,  ZS./O  lbs. 

III 

1.(92 

0.322 

0.217 

9.(30 

25.51 

1725 

/550 

0 

109 

2.652 

0.322 

0.29/ 

9.690 

26.00 

1105 

/615 

f 1 

/0  Foot  Lengths. 

Average 

8 .666 

0.272 

9.692 

29.90 

1583 

15(7 

t 1.2 

Corrected  to  Nom.  Thk.  0.271 

$7 

9.695 

0.27/ 

0.263 

19.6  56 

23.59 

1590 

K7S 

+ 13.5 

9 /T  Casing  , 29.39  /hs. 

129 

1.699 

0.29/ 

0263 

19.(91 

2 3 .56 

1250 

1335 

- 9.5 

S'"  Line  Pipe, ZS. to  ibs. 

*79 

1.669 

0.211 

0.266 

17.916 

23.19 

1925 

1936 

— 

— 

90 

9.656 

0.25/ 

0.266 

19.(96 

23.95 

133  5 

1990 

- 2.5 

» ••  •<  ••  •• 

8 Z 

2.662 

0.21/ 

0. 27/ 

/9.136 

2 9.27 

/990 

199 0 

*-  / 

•• 

S9 

9.662 

0.27/ 

0.272 

19.(16 

29.33 

mo 

1700 

1975 

t/S 

I'/,’  Casing,  29.31  lbs. 

55 

2.690 

0.27/ 

0.273 

19.(36 

29.35 

/ 51 0 

' 15(5 

F 6 

ii  ••  •;  •• 

56 

9.650 

0.27/ 

0.275 

19.(96 

29.55 

1920 

/ 310 

- 6.5 

9! 

9.666 

0.29/ 

0.276 

19.(91 

29.73 

13  05 

1255 

-IS 

S'"  Line.  Pip e,  2 5.10  Has. 

59 

9.(65 

0.27/ 

0.271 

19.656 

29.17 

139  0 

13/5 

-// 

9/.,"  Casing,  29.31 /bs. 

Id/ 

9.695 

0.322 

0.296 

19.630 

2 5.11 

nzs 

1525 

t 3.5 

1"  Line  Pi/oe,  29.  H lbs. 

IS  Lengths,  to  Nom.Thk.o.l7L 

Average. 

1.653 

0.273 

19.690 

29.3J 

193  5 

19(1 

- 0.5 

■>r  "See  20  Foot  Lengths. 

1 

2 

3 

4 

5 

b 

7 

8 

9 

!0 

u 

Fig.  19. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  37 


EFFECT  OF  LENGTH  ON  COLLAPSING  PRESSURE—  Abstract  from  Loq  of 
Tests  Conducted  by  Prof.  R.T.  Stewart,  1302-04,  on  National  Tube  Co.'s  La/o- 
vv  elded  Bessemer  Steel  Tubes  in  Lenqths  of  ZZ*,  5,  10,  IS,  and  20  Feet,  *%“ Outside 
Diameter,  to  Determine  the  Effect  of  Length  of  Tube  on  the  Collapsing  Pressure-, 
to  which  is  Added  a Comparison  with  Values  Read  from  the  Curve,  M,  Represent- 
ing the  Average  Results  of  these  Tests.  Made  by  r.e.s.  under  direction  of  R.r.s.jsos. 


Tests  Grouped  and  Arranged  in  Order  of  Length  and  Thickness  of  Tubes. 


Number 

of  Test 

Actual 

Outside 

Diameter, 

Thickness  of  Wall, 
Inches 

Unsupported 

Length 
of  Tube 
Feet. 

Actual 
Plain  End 
Weight, 
Lbs  per  Ft. 

Collapsing 
Pounds  per 

Pressur e 
Square  Inch. 

Designation  of  Tube, 

Q$  Reported. 

Nominal 

Computed 
from  Wgjt. 

Observed 

Corrected  to 
Nom.Thk. 

From 
Curve  M 

%Variation 
from  M. 

Si 

7.004 

0.27  f 

0.259 

19.049 

23.13 

1320 

1450 

t 2 

7/y  Casing,  24.39  ibs. 

54 

9.000 

0.27/ 

0.202 

19.034 

23.5Z 

1495 

1550 

H/.5 

•>  i.  j. 

99 

9.003 

0.322 

0.204 

19.040 

23.00 

1375 

1450 

* 2 

9"  Line  Pipe, 22.19  lbs. 

* 7 9 

9.004 

6.Z  9/ 

0.200 

17.990 

23.94 

1425 

1496 

t 2.5 

•«  • ••  ,25.60  tbs. 

SO 

9.000 

0.27/ 

0.27/ 

14.040 

24.29 

1435 

1435 

t I 

9/e  Casing  , 24.39  lbs. 

5 3 

9.000 

0.Z7I 

0.272 

19.039 

24.32 

1520 

1516 

1420 

t 6.5 

„ It, 

7 0 

9.00  3 

0.29/ 

0.272 

19.034 

24.39 

1410 

1406 

- 1.5 

7"  Line  Pipe,  25.66  lbs. 

St 

9.009 

O.Z7  f 

0.274 

14.034 

24.5  V 

14  30 

1395 

- 2 

V'/j'C  a sing,  2.4. 39  ibs. 

7 S 

9.040 

0.291 

0.274 

19.044 

24.44 

1375 

1345 

- 5.5 

7 " Line  Pipe,  25-66/ bs. 

*7  7 

9.000 

0.29/ 

0.274 

19. SOI 

Z4.47 

1275 

1245 

-12.5 

1,  ..  •• 

*7  9 

9.000 

0. 29/ 

0.290 

19.340 

25.69 

1256 

1145 

- 26 



9.000 

0.ZC9 

19.042 

24.05 

IN  19 

1440 

/ 1.2 

Z6  Lenqths.CorrectedbThk.ZlI. 
Klron,  not  in  overages. 

119 

9.045 

4.29V 

2.159 

20.22 

2450 

2 7 96 

tl  6.5 

Hi 

7.045 

0.249 

2.100 

20.00 

2305 

20  55 

t S.5 

2/^Foot  Lengths. 

HI 

9.0S7 

0.322 

0.314 

2.170 

29.43 

2240 

2325 

ISIS 

- 7.5 

//? 

9.04! 

0.322 

2.140 

29.06 

2490 

2496 

- / 

7" Line  Pijae,Z9./9  lbs. 

no 

9.040 

0.323 

2.150 

29.04 

2340 

2390 

- S.S 

9.040, 

0.31 1 

2.157 

27.70 

2347 

2 520 

t ■ 0.4 

ns 

9.0S9 

0.247 

4.045 

2 0.45 

1496 

2270 

- / 

1/ 7 

9.034 

0X44 

4.041 

2 0.55 

2325 

2595 

//3 

S Foot  Lengths, 

113 

9.043 

0.322 

0.307 

4.040 

27.36 

1795 

1470 

22 90 

' 14 

IIP 

9.073 

0.367 

4.035 

27.43 

2046 

2220 

- 3 

7“  Line  Pipe,  29/9 lbs. 

I/O. 

9.003 

0.321 

4.056 

29.00 

2225 

2240 

- 2 

7.0S4 

0.300 

4.042 

27.29 

2473 

2254 

- 1.4 

no 

9.020 

0.300 

4.04b 

27.20 

2655 

2235 

- 4.5 

tnz 

9.07Z 

0.3ZZ 

0.314 

9.045 

29.04 

1595 

10  75 

2/ 35 

-Z/.5 

16  Foot  Lengths. 

t/OS 

9.05Z 

0.325 

9. 040 

29.96 

1790 

1750 

* ■ 4 

7"Line  Pipe,29./9  lbs. 

9.0ZC 

0.300 

4.040 

27.26 

2653' 

2235 

- 4.S 

tO.H.  Steel, not  in  averages. 

123 

9.005 

0.291 

0.247 

14.041 

20.49 

1075 

1440 

- 4.5 

7" Line  Pipe,  ZS. 66  lbs. 

/OS 

9.049 

0.322 

0.24  7 

14.045 

20.40 

1526 

1795 

- 12.5 

29. /Hbs. 

10  0 

9.072 

0.322 

0.309 

14.035 

27.49 

1095 

1935 

2035 

- 9.5 

.,  „ 1, 

103 

9.04 1 

0.322 

0.3Z6 

14. 040 

29.39 

2606 

2625 

- 6.S 

• « *. 

10  7 

•/.coo 

0.322 

6.324 

14.036 

29.94 

2025 

2 005 

- t.s 



9.059 

0.304 

14.039 

27.54 

179/ 

1919 

- 5.0 

IS  Foot  Lengths. 

101 

9.047 

0.244 

1 4.04 / 

20.27 

7 050 

1935 

- 1.5 

too 

9.040 

0.297 

14.045 

2 0.44 

mo 

1970 

t ■ 0.5 

424 

9.07 / 

0.302 

14.995 

20.49 

1575 

1790 

- 9.5 

423 

9.044 

0.363 

19.792 

27.06 

1930 

2025 

* 3 

20  Foot  Lengths. 

42! 

9.000 

0.3ZZ 

0.303 

19.700 

27.64 

19  35 

2135 

1905 

/ 9.5 

I0Z 

9.050 

0.363 

14.055 

27.66 

1400 

2106 

t/6 

9"  Line  Pipe,  29.15  ibs. 

422 

9.07Z 

0.36  7 

19.705 

27.34 

IC3S 

1790 

- 4 

t9 9 

9.000 

6.309 

19.030 

27 .44 

1735 

1540 

- V 

420 

9.059 

0.3/6 

19.975 

Z7.C4 

1905 

1936 

- 1.5 

9.0  59 

6.362 

19.753 

zo.?r 

I7CZ 

1400 

F 0.1 

/ 

2 

3 

4 

5 

6 

7 

9 

9 

10 

II 

Noter  To  obtain  collapsing  pressures  for  curve  N , multiply  corresponding  tabular  collapsing  press- 
ures from  curve  M by  0.944  . Curve  Mis  based  upon  Series  One  only,  wh He  curve  /V  is  based  jointly  upon 
both  Series  One  and  Series  Two. 


Fig.  20. 


38 

3000 

2900 

2800 

2700 

2600 

2500 

2400 

2300 

2200 

2100 

2000 

1900 

1800 

1700 

1600 

1500 

1400 

1300 

1200 

1100 

1000 

900 

800 

700 

GOO 

500 

400 

300 

200 

100 

1 

Fig 

n t 

test 

all  1 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


21. — Chart  showing  Relation  of  Length  of  Tube  to  Collapsing  Pres- 
sure for  National  Tube  Co.’s  Lap-welded  Bessemer  Steel  Tubes. 
Based  upon  Tests  on  Lengths  of  2$,  5,  10,  15,  and  20  Feet,  Con- 
ducted by  Prof.  R.  T.  Stewart,  1902-4. 

le  lines  marked  M show  the  relation  of  length  to  collapsing  pressure,  from 
} on  tubes  8f"  O.D.,  and  the  lines  N,  5.6%  below,  this  relation  as  based  on 
ests  on  outside  diameters  from  3 to  10  inches. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  39 

for  each  of  the  five  lengths  of  tube  tested,  the  actual  average  thick- 
ness of  wall  of  each  experimental  tube  shall  fall  in  the  group  having 
the  nearest  nominal  thickness  of  wall. 

Collapsing  Pressure  Corrected  to  Nominal  Thickness. — In  the 
seventh  column,  or  the  first  of  those  headed  “Collapsing  Pres- 
sure/’ Pigs.  18-20,  are  entered  the  observed  collapsing  pressures. 
These  pressures,  of  course,  in  each  case  correspond  to  the  actual 
thickness  of  the  tube.  Since  the  actual  thicknesses  of  different 
commercial  tubes  of  the  same  nominal  thickness  of  wall  vary 
somewhat  in  practice,  as  is  evident  from  running  the  eye  down 
column  4 of  this  table,  it  became  necessary,  in  order  to  get  strictly 
comparable  results,  to  obtain  from  the  observed  collapsing  pres- 
sure of  each  experimental  tube,  whose  thickness  of  wall  did  not 
equal  exactly  the  nominal  thickness,  a collapsing  pressure  that 
would  correspond  to  this  nominal  thickness.  That  is  to  say,  the 
observed  collapsing  pressures  corresponding  to  the  respective  thick- 
nesses of  wall  tested  were  corrected,  so  that  each  would  represent 
what  the  collapsing  pressure  would  have  been  had  the  tube  had 
the  exact  nominal  thickness  instead  of  that  tabulated  in  column 
4.  These  collapsing  pressures,  having  been  thus  corrected  to  cor- 
respond to  the  nominal  thickness  of  wall,  are  entered  in  column 

8,  or  the  second  of  those  headed  “ Collapsing  Pressure.” 

This  correction  was  made  graphically  by  first  plotting,  to  a ver- 
tical scale  representing  collapsing  pressure  and  a horizontal  scale 
representing  thickness  of  wall,  the  results  of  the  tests  for  all  the 
different  thicknesses  of  wall  for  each  of  the  five  lengths  of  tube; 
second,  drawing  the  mean  line  representing  average  results ; and, 
third,  drawing  a line  parallel  to  this  mean  line  through  the  plotted 
value  for  each  tube  intersecting  the  ordinate  corresponding  to  the 
thickness  of  that  tube.  The  collapsing  pressure  corresponding  to 
this  point  of  intersection  was  then  read  and  recorded  in  column  8. 

The  Collapsing  Pressure  from  Curve  M for  each  nominal 
thickness,  in  the  five  different  lengths  tested,  are  entered  in 
column  9.  These  were  read  from  a chart  similar  to  Fig.  21, 
but  drawn  to  a much  larger  scale.  The  variation  of  the  values 
given  in  column  8 from  the  corresponding  values  in  column 

9,  in  per  cent.,  are  given  in  column  10.  This  column  shows 
at  a glance  how  the  individual  tests  corrected  to  nominal  thickness 
differ  from  the  mean  values  as  read  from  curve  M.  When  it  is 
considered  that  these  were  the  ordinary  commercial  lap-welded 
wrought-tubes,  selected  at  random,  and  subjected  to  an  external 


40  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

fluid  pressure,  it  is  surprising  that  there  should  be  such  a slight 
variation.  It  will  be  observed  that  the  greatest  individual  vari- 
ation does  not  exceed  22  per  cent.,  while  the  greatest  variation 
among  the  group  averages  is  8.2  per  cent.,  the  greater  portion  of 
these  being  less  than  5 per  cent.  The  average  variation  of  the 
group  averages  is  0.2  per  cent.  Theoretically,  of  course,  this  should 
be  zero,  but  the  very  small  value  of  0.2  per  cent,  obtained  serves 
as  a satisfactory  check  upon  the  accuracy  of  the  mean  values  read 
from  curve  M. 

Relation  of  Collapsing  Pressure  to  Length  of  Tube. — This  re- 
lation is  clearly  shown  in  Fig.  21  for  8^-inch  casing  (8f  inches 
outside  diameter)  in  the  four  nominal  thicknesses  of  0.180,  0.229, 
0.271,  0.322  inch,  and  for  lengths  of  from  2 to  20  feet  between 
the  regular  screwed  couplings. 

On  this  chart  the  combined  circles  and  crosses  represent  the  dif- 
ferent plotted  averages  contained  in  column  8,  Figs.  18-20.  By 
means  of  these  plotted  values  the  curves  marked  M were  con- 
structed. The  spacing  of  these  curves  was  adjusted  so  that  when 
the  values  of  the  table,  Figs.  18-20,  were  also  plotted  to  collap- 
sing pressure  and  thickness,  for  each  of  the  five  lengths  tested,  the 
resulting  curves  were  smooth.  By  this  method  of  cross-plotting 
the  individual  experiments  on  8f-inch  outside  diameter  tubes, 
the  four  curves  marked  M were  obtained.  Each  of  these  curves, 
then,  is  not  based  only  upon  the  group  averages  belonging  to  it, 
but  is  also  based  upon  the  group  averages  belonging  to  the  other 
three  curves  similarly  marked. 

The  curves  marked  N were  obtained  by  adjusting  the  curves  M 
so  as  to  harmonize  with  the  most  probable  values  for  collapsing 
pressure  as  based  upon  Series  Two.  The  difference,  it  will  be 
observed,  is  small,  the  different  curves  H being  only  5.6  per  cent, 
below  the  corresponding  curves  M. 

Discussion  of  Curves  M and  N. — An  inspection  of  Fig.  21  dis- 
closes the  fact  that  for  this  size  of  tube,  especially  for  the  thinner 
walls,  there  is  a marked  dropping  off  in  collapsing  pressure  as 
the  length  of  tube  is  increased  up  to  about  4^  feet,  or  until  a 
length  equal  to  about  6 diameters  is  reached.  Beyond  this  point 
there  appears  to  be  no  further  material  decrease  in  the  collapsing 
pressure.  For  example,  from  curve  M,  for  a thickness  of  0.180 
inch,  the  collapsing  pressures  for  lengths  of  2,  4J  and  20  feet  are 
respectively  1,050,  570,  480  pounds.  That  is  to  say,  an  increase 
in  length  from  2 to  4J  feet  diminishes  the  collapsing  pressure  by 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  41 

480  pounds,  while  a further  increase  from  4-J  to  20  feet  in  length 
diminishes  the  collapsing  pressure  by  only  90  pounds.  As  the 
thickness  of  wall  is  increased  this  disparity  between  the  relative 
strength  of  long  and  short  tubes  becomes  less  prominent  until  for 
a thickness  of  0.322  inch  the  difference  is  so  small  as  to  be  of  no 
practical  importance.  For  example,  assuming  20  feet  to  be  the 
standard  length  of  tube  between  end  connections  tending  to  hold 
it  to  a circular  form,  we  find  from  curve  N,  for  a thickness  of 
0.180  inch,  that  for  lengths  of  20,  15,  10,  5 and  2 feet,  the  respec- 
tive collapsing  pressures  would  be  450,  470,  500,  540,  and  980 
pounds,  which  correspond  to  increasees  of  4.5,  11,  20,  and  118 
per  cent,  respectively;  while  for  a thickness  of  0.322  inch  the 
values  of  the  collapsing  pressures  for  the  same  lengths  are  1,850, 
1,915,  2,000,  2,140  and  2,390  pounds,  which  correspond  to  in- 
creases of  3.5,  8,  16,  and  29  per  cent,  respectively. 

A study  of  these  curves  M and  U,  taken  in  connection  with  the 
photographs  of  the  experimental  tubes  after  being  collapsed,  and 
column  19  of  the  tabular  statements  of  principal  results  of  tests, 
will  show  conclusively  that  for  lengths  greater  than  about  six 
diameters  the  strength  of  a tube  when  subjected  to  a fluid  col- 
lapsing pressure  is  substantially  constant.  It  must  be  remem- 
bered, while  studying  the  photographs  and  column  19  of  the  tables 
referred  to,  that  the  inability  to  stop  the  hydraulic  pressure  pump 
instantly  the  experimental  tube  failed,  together  with  the  recoil 
of  the  hydraulic  test  cylinder,  will  ordinarily  account  for  an  ex- 
tension of  the  length  of  the  collapsed  portion  by  probably  two  or 
more  diameters,  after  failure  had  actually  occurred. 


Previously  Published  Formulae  for  the  Collapsing  Pres- 
sures of  Tubes. 

Preparatory  to  entering  upon  the  experimental  investigation  of 
which  this  is  a report,  an  extensive  search  was  made  through  the 
technical  literature  where  one  would  expect  to  find  matters  re- 
lating to  the  collapsing  pressures  of  tubes  and  flues.  As  a result  of 
this  search  a number  of  formulae  were  collected  and  compared. 

Since  completing  the  present  research  comparisons  were  made 
of  the  results  of  the  actual  tests  and  the  corresponding  values 
calculated  by  the  different  published  formulae.  These  are  shown 
in  Figs.  22  to  33  inclusive.  It  will  be  observed  that  these  com- 
parisons have  been  made  for  plain  tubes,  8§  inches  outside 


42  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

diameter,  in  four  commercial  thicknesses,  and  for  lengths  of  2-J, 
5,  10,  15,  and  20  feet  between  end  connnections  tending  to  hold 
them  to  a circular  form. 

In  the  table  and  charts  above  referred  to  and  in  the  discussion 
that  here  follows : 

P = probable  fluid  collapsing  pressure,  in  pounds  per  square  inch, 
as  based  upon  the  present  research,  and  for  the  conditions 
stated. 

p = collapsing  pressure  as  calculated  by  the  different  published 
formulae  for  the  same  condition  as  for  P. 
d = outside  diameter  of  tube  in  inches. 
t = thickness  of  wall  in  inches. 

1 = length  of  tube  in  inches. 

L = length  of  tube  in  feet. 

P/p  = The  relation  of  the  actual  collapsing  pressure,  for  any 
stated  conditions,  to  that  calculated  by  the  different  pub- 
lished formulae  for  the  same  conditions. 

Fairbairris  Formula. — From  his  own  experiments  Fairbairn 
established  the  following  empirical  formula : 

/2.19  /2.19 

p = 9,676,000  -jj  = 806,300  ^ • 

He  states  that  “ the  above  is  the  general  formula  for  the  calcu- 
lation of  the  strength  of  wr ought-iron  tubes  subjected  to  external 
pressure,  within  the  limits  indicated  by  the  experiments,  that  is, 
provided  that  the  length  is  not  less  than  1.5  feet,  and  not  greater 
than  probably  10  feet.”  It  would  appear  that  this  upper  limit 
was  arbitrarily  fixed,  since  none  of  the  tubes  tested  by  him  ex- 
ceeded about  five  feet  in  length,  and  were  held  rigidly  to  a cir- 
cular form  at  the  ends. 

Fig.  23  shows,  plotted  to  scale,  the  values  entered  in  columns 

2 and  3 of  Fig.  22.  In  this  chart  the  vertical  scale  represents 
fluid  collapsing  pressure,  in  pounds  per  square  inch,  and  the  hori- 
zontal scale,  length  of  tube,  in  feet,  between  end  connections  tend- 
ing to  hold  it  to  a circular  form. 

The  four  curves  shown  in  full  lines  are  based  upon  the  tests 
conducted,  during  the  present  research,  on  8 f -inch  outside  diam- 
eter tubes  in  the  four  different  thicknesses  of  wall  shown  and  for 
the  five  lengths  above  stated.  These  lines  are  the  same  as  curves 
H.  (See  page  40  and  Fig.  21.) 

The  broken  and  dotted  lines  represent  the  results  obtained  by 


COLLAPSING  PEESSUEES  OF  LAP-WELDED  STEEL  TUBES. 


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43 


Beyond  Foirboirn's  i'mlt  of  Unyth.  f Beyond  Unwins  limit  of  Un9th. 

Fig.  22. — Comparison  op  Values  for  the  Collapsing  Pressures  op  8f"  0.  D.  Tubes,  Calculated  by  the  dif- 
ferent Published  Formulae,  with  Corresponding  Values  Based  upon  Tests  by  Prof.  R.  T.  Stewart. 


44  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  23. — FAIRBAIRN.  Chart  showing  Comparison  of  Values  for  Col- 
lapsing Pressures  of  8f"  O.D.  Tubes,  obtained  by  use  of  Fairbairn’s 
Formula,  with  values  based  on  Tests  on  National  Tube  Co.’s  Besse- 
mer Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Fairbaim’s  Formula,  full  lines 
those  based  on  Prof.  Stewart’s  experiments. 

Fairbairn  states  that  his  formula  is  applicable  to  lengths  from  1$  to  10  feet. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  45 

plotting  to  the  same  scales  the  corresponding  values  for  collapsing 
pressure  as  calculated  by  Fairbairn’s  formula. 

For  both  sets  of  curves  the  thickness  of  wall  in  decimals  of  an 
inch  is  written  at  both  ends  of  the  curve  representing  the  tube. 

It  should  be  observed  that  the  portions  of  the  curves  consisting 
of  long  dashes  represent  the  application  of  Fairbairn’s  fomula 
within  the  limits  of  length  assigned  by  him,  while  the  portions 
consisting  of  short  dashes  are  beyond  this  limit.  These  latter  have 
been  drawn  for  the  purpose  of  showing  how  utterly  inapplicable 
is  this  formula  to  modern  commercial  tubes  of  comparatively  long 
lengths  between  joints  or  end  supports  tending  to  hold  them  to 
a circular  form,  such  as  well  casing,  boiler  tubes  and  long,  plain 
boiler  flues. 

Applicability  of  Fairbairns  Formula . — It  would  appear  from 
this  chart  that  Fairbairn’s  formula  is  applicable  only  to  tubes 
having  a comparatively  thin  wall  and,  at  the  same  time,  a rela- 
tively short  length  between  joints  tending  to  hold  the  tube  to  a 
circular  form.  That  this  should  be  the  case  is  quite  natural,  since 
the  experiments  furnishing  the  data  upon  which  this  formula  was 
based  involved  these  conditions  of  relatively  thin  walls  and  short 
lengths.  This  is  quite  apparent  from  an  inspection  of  the  chart 
which,  it  will  be  observed,  is  for  tubes  having  outside  diameters 
of  8f  inches  in  lengths  of  from  2-|  to  20  feet,  and  for  thicknesses 
of  wall  of  0.180,  0.229,  0.271  and  0.322  inch. 

The  only  place  on  the  chart  where  values  calculated  by  Fair- 
bairn’s formula  agree  substantially,  over  any  appreciable  length 
of  tube,  with  those  obtained  by  the  present  research  on  modern 
commercial  tubes  is  for  the  tubes  having  a thickness  of  wall  equal 
0.180  inch,  which  were  the  thinnest  tested,  and  then  only  for  a 
length  up  to  about  4.5  feet,  or  six  diameters  of  tube.  The  chart 
shows  that  at  Fairbairn’s  limit  of  length  of  10  feet  a tube  having 
an  outside  diameter  of  8§  inches  and  a thickness  of  wall  of  0.180 
inch  would  probably  collapse  at  500  pounds  per  square  inch.  For 
these  same  conditions  Fairbairn’s  formula  gives  a pressure  of 
220  pounds,  or  44  per  cent,  of  this  value,  the  actual  collapsing 
pressure  being  thus  2.3  times  that  calculated  by  this  formula. 
Again,  for  a plain  tube  of  twice  this  length,  or  20  feet  between 
end  connections  tending  to  hold  it  to  a circular  form,  and  for  the 
same  diameter  and  thickness  of  wall,  we  get  450  pounds  for  the 
former  and  110  pounds  for  the  latter.  For  this  case  it  appears 
that  the  value  calculated  by  use  of  Fairbairn’s  formula  is  only 


46  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

24  per  cent,  of  that  obtained  by  experiment,  the  latter  for  this 
case  being  4.1  times  the  former.  It  is  thus  seen  that  when  applied 
to  an  8f-inch  tube,  0.180  inch  thick,  and  20  feet  long  between 
joints,  Fairbairn’s  formula  gives  a result  for  the  collapsing  pres- 
sure that  is  a trifle  over  300  per  cent,  in  error. 

It  will  be  observed  that  Fairbairn’s  formula  is  even  less  ap- 
plicable to  a tube  having  a thicker  wall.  For  example,  Fig.  23 
shows  that  for  the  same  diameter  of  tube  as  before,  but  having  a 
thickness  of  wall  equal  0.271  instead  of  0.180  inch,  the  true  values 
for  probable  collapsing  pressures  at  Fairbairn’s  limit  and  for 
lengths  of  20  feet  are,  respectively,  2.7  and  5.0  times  that  obtained 
by  use  of  his  formula.  In  other  words,  this  formula  for  these  con- 
ditions gives  results  that  are  apparently  in  error  by  respectively 
170  and  400  per  cent. 

For  8f-inch  commercial  tubes  having  thicker  walls  than  0.180 
inch  it  will  be  observed  that  Fairbairn’s  formula  gives  the  correct 
collapsing  pressure  for  but  one  length,  namely,  that  at  which  the 
broken  line  cuts  the  corresponding  full  line.  The  chart  shows 
clearly  that  Fairbairn’s  formula  does  not  apply  to  modern  lap- 
welded  tubes  having  either  relatively  thick  walls  or  long  lengths  be- 
tween joints  or  end  connections  tending  to  hold  them  to  a circular 
form. 

Material  of  Fairbairn  s Tubes . — Ho  attempt  has  been  made,  in 
this  report,  to  modify  the  constant  of  Fairbairn’s  formula  so  as  to 
adapt  it  to  steel  tubes.  This  was  because  of  two  reasons:  First, 
no  determination  appears  to  have  been  made  for  the  physical  prop- 
erties of  the  wrought  iron  constituting  Fairbairn’s  experimental 
tubes,  at  least  an  examination  of  the  records  of  his  research  has 
not  disclosed  any  information  on  this  point.  Second,  even  had  we 
a record  of  the  physical  properties  of  the  material  of  his  tubes, 
there  appears  to  be  no  simple  relation  between  the  collapsing  pres- 
sure of  a tube  and  the  physical  properties  of  the  material  of  which 
it  is  formed.  For  a discussion  of  this,  see  page  73. 

However,  since  Fairbairn’s  experimental  tubes  were  made  from 
rolled  plates,  Ho.  19  B.W.G.,  or  0.042  inch  thick,  of  presumably 
high-grade  iron,  the  flat  plates  being  rolled  cold  into  tubular  form, 
then  riveted  and  brazed,  it  would  appear  that,  for  these  conditions, 
the  material  of  these  tubes  would  not  differ  greatly  in  physical 
properties  from  those  of  the  very  soft  steel  used  in  modern  com- 
mercial lap-welded  tubes. 

Fairbairn' s Approximate  Formula . — This  formula  was  obtained 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  47 


Fig.  24. — FAIRBAIRN.  Chart  showing  comparison  of  values  for  col- 
lapsing PRESSURES  OF  8f"  O.D.  TUBES,  OBTAINED  BY  USE  OF  FAIRBAIRN’S 
Approximate  Formula,  with  values  based  on  Tests  on  National  Tube 
Co.’s  Bessemer  Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Fairb aim’s  Approximate 
Formula  full  lines  those  based  on  Prof.  Stewart’s  experiments. 

Fairbaim  states  that  his  formula  is  applicable  to  lengths  from  1J  to  10  feet. 


48  COLLAPSING  PRESSURES  OE  LAP-WELDED  STEEL  TUBES. 


from  the  preceding  more  exact  one  by  changing  the  factor  t2‘ 19 
to  t2,  thus  giving  rise  to  a formula  that  could  be  more  readily 
handled  in  the  making  of  calculations.  The  formula  thus  modi- 
fied is 

p = 9,676,000  ~ = 806,300  ~ • 

The  precise  manner  in  which  this  change  affects  the  results 
can  best  be  had  by  making  a comparison  of  Fig.  24  with  Fig. 
23.  Also  by  comparing  columns  5 and  6 with  3 and  4 of  Fig.  22. 

Such  a comparison  will  show  that,  while  not  representing  the 
conditions  of  Fairbairn’s  experiments,  namely,  relatively  thin  walls 
and  short  lengths,  as  well  as  the  more  exact  formula,  it  is  also 
quite  inapplicable  to  modern  wrought  tubes  in  relatively  long 
lengths. 

Grashofs  Formula. — Grashof  selected  from  Fairbairn’s  ex- 
periments 17  of  those  having  walls  0.042-inch  thick  and  4 having 
walls  to  J inch  thick  and  from  these  21  experiments  he  deduced 
the  following  formula : 

v 2.315  V 2.315 

^ = 24,480,000^  = 2, 040, 000  . . . .(A) 

As  this  formula  was  found  to  represent  the  results  of  Fair- 
bairn’s experiments  on  the  tubes  having  walls  0.042-inch  thick  bet- 
ter than  those  having  walls  to  J inch  thick,  he  derived  the  follow- 
ing formula  for  the  latter,  namely : 

P = 1,033,600  J^m  = 86,130  . • . -(B) 

This  formula  has  been  applied  to  tubes  having  an  outside  di- 
ameter equal  8f  inches,  in  lengths  from  2|-  to  20  feet  and  for 
four  commercial  thicknesses  of  wall  from  0.180  to  0.322  inch. 
The  precise  manner  in  which  these  calculated  values  differ  from 
the  true  probable  collapsing  pressures  is  clearly  shown  in  Fig.  25 
and  in  column  14  of  the  table,  Fig.  22. 

Ny  strom’s  Formula. — Nystrom  also  used  Fairbairn’s  experi- 
ments for  the  deduction  of  his  formula  for  the  collapsing  strength 
of  flues. 


CO1  I APSING  PRESSURE  OF  LAP-WELDED  STEEL  TUBES.  49 


Fig.  25. — GRASHOF.  Chart  showing  comparison  of  values  for  col- 
lapsing PRESSURES  OF  8f"  O.D.  TUBES,  OBTAINED  BY  USE  OF  GrASHOF’s 
Formula  B,  with  values  based  on  Tests  on  National  Tube  Co.’s 
Bessemer  Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Grashof’s  Formula,  full  lines 
those  based  on  Prof.  Stewart’s  experiments. 


50  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  26. — NYSTROM.  Chart  showing  comparison  of  value  for  collaps- 
ing PRESSURES  OF  81"  O.D.  TUBES,  OBTAINED  BY  USE  OF  NYSTROM’S 

Formula,  with  values  based  on  Tests  on  National  Tube  Co.’s  Bes- 
semer Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Nystrom’s  Formula,  full  lines 
those  based  on  Prof.  Stewart’s  experiments. 


COLLAPSING  PRESSURES  OF  LAP -WELDED  STEEL  TUBES.  51 


Where  T is  the  tensile  strength  of  the  material. 
50,000  for  T and  for  L in  this  formula  gives 


p = 692,800 


f 


dVl 


Substituting 


FTystrom  considered  4 a sufficient  factor  of  safety  for  use  with 
his  formula. 

The  customary  value  of  50,000  for  T has  been  used  in  this 
formula  for  two  reasons:  (1)  In  order  that  the  results  obtained 
might  be  comparable  with  the  other  heretofore  published  formulas, 
all  of  which  are  presumably  for  wrought  iron;  and  (2)  because, 
since  the  collapsing  strength  of  a tube,  in  the  light  of  the  present 
research,  appears  to  be  quite  independent  of  the  tensile  strength 
of  the  material  constituting  it,  it  was  thought  best  not  to  attempt 
any  modification  of  the  formula.  (See  page  73.) 

A comparison  of  pressures  obtained  from  Eystronfis  fomula  and 
the  probable  collapsing  pressures  of  modern  lap-welded  tubes  is 
shown  in  Fig.  26  and  column  8 of  Fig.  22. 

Unwin’s  Formulae. — Unwin,  who  had  been  associated  with  Fair- 
bairn  when  he  made  his  collapsing  tests  on  tubes,  has  derived  the 
following  formulae  for  thick-walled  tubes,  namely,  walls  ^ to  £ 
inch  thick. 

For  tubes  with  a longitudinal  butt-joint : 


p = 9,614,000 


t 221 


Z0-9  d1 


.16* 


. . . (A) 


For  tubes  with  a longitudinal  lap-joint: 

V — 7,363,000  £0  9 ^rltl6« 


(B) 


Unwin  states  that  when  the  length  of  tube  between  end  con- 
nections or  transverse  joints  tending  to  hold  it  to  a circular  form 
is  at  least  10  or  12  diameters,  the  strength  does  not  decrease 
with  further  increase  of  length. 

A comparison  of  values  from  these  formulae  with  the  probable 
collapsing  pressures  of  modern  tubes  is  given  in  Figs.  27  and  28, 
and  columns  10  and  12  of  Fig  22. 

Clark’s  Formulae. — For  the  derivation  of  his  formula  A,  Clark 
selected,  from  the  reports  of  the  Manchester  Steam-Users  Associa- 
tion, the  dimensions  of  six  boiler  flues  which  collapsed  while  in 


52  COLLAPSING  PRESSURES  OE  LAP-WELDED  STEEL  TUBES. 


Fig.  27. — UNWIN.  Chart  showing  comparison  of  Values  for  Collapsing 

Pressures  of  8§"  O.D.  Tubes,  obtained  by  use  of  Unwin’s  Formula 

A,  WITH  VALUES  BASED  ON  TESTS  ON  NATIONAL  TUBE  Co.’s  BESSEMER 

Stee  . Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Unwin’s  Formula  “for  tubes 
with  a longitudinal  butt-joint,”  full  lines  those  based  on  Prof.  Stewart’s  experi- 
ments. 

Unwin  states  that  when  the  length  is  at  least  10  or  12  diameters  the  strength 
does  not  decrease  with  further  increase  of  length. 


2700 

2600 

2500 

2400 

2300 

2200 

2100 

2000 

1900 

1800 

1700 

1600 

1500 

1400 

1300 

1200 

1100 

1000 

900 

800 

700 

600 

500 

400 

300 

200 

100 

0 

It 

Fig. 

I 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  53 


28. — UNWIN.  Chart  showing  comparison  of  values  for  collapsing 

PRESSURES  OF  81"  O.D.  TUBES,  OBTAINED  BY  USE  OF  UNWIN’S  FORMULA 
B,  WITH  VALUES  BASED  ON  TESTS  ON  NATIONAL  TUBE  Co.’s  BESSEMER 
Steel  Lap-welded  Tubes. 

broken  lines  show  values  obtained  by  use  of  Unwin’s  Formula  “for  tubes 
a longitudinal  lap-joint,”  full  lines  those  based  on  Prof.  Stewart’s  experi- 


Inwin  states  that  when  the  length  is  at  least  10  or  12  diameters  the  strength 
not  decrease  with  further  increase  of  length. 


54  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  29. — CLARK.  Chart  showing  comparison  of  values  for  collapsing 
Pressures  of  8f"  O.D.  Tubes,  obtained  by  use  of  Clark’s  Formulas, 

WITH  VALUES  BASED  ON  TESTS  ON  NATIONAL  TUBE  Co.’s  BESSEMER 

Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Clark’s  Formulae,  A & B,  full 
lines  those  based  on  Prof.  Stewart’s  experiments. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  55 


Fig.  30. — LOVE.  Chart  showing  comparison  of  values  for  collapsing 
fit  Pressures  of  8£"  O.D.  Tubes,  obtained  by  use  of  Love’s  Formula,  with 

VALUES  BASED  ON  TESTS  ON  NATIONAL  TUBE  Co.’s  BESSEMER  STEEL 

Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Love’s  Formula,  full  lines  those 
base  d on  Prof.  Stewart’s  experiments. 


2400 

2300 

2200 

2100 

2000 

1900 

1300 

1700 

1600 

1500 

1400 

1300 

1200 

1100 

1000 

900 

800 

700 

600 

500 

400 

300 

200 

100 

0 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


>.  31. — BELPAIRE.  Chart  showing  Comparison  of  Values  for  Col- 
lapsing Pressure  of  8f"  O.  D.  Tubes  obtained  by  use  of  Belpaire’s 
Formula,  with  values  based  on  tests  on  Natio  a . Tube  Co.’s 
Bessemer  Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Belpaire’s  Formula,  full  lines 
se  based  on  Prof.  Stewart’s  experiments. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  57 


Fig.  32. — WEHAGE.  Chart  Showing  Comparison  of  Values  for  Collaps- 
ing Pressures  of  8f"  O.D.  Tubes,  obtained  by  Use  of  Wehage’s 
Formula,  with  Values  Based  on  Tests  on  National  Tube  Co.’s  Besse- 
mer Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Wehage’s  Formula  for  welded 
or  butt-joints,  from  Dingler’s  Journal,  Vol.  242,  1881,  page  236,  and  the  4th 
German  ed.  Reuleaux’s  Const.,  page  1084.  The  full  lines  show  values  based  on 
P of.  Stewart’s  experiments. 


58  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  33. — WEHAGE.  Chart  showing  comparison  of  values  for  co  laps- 
ing PRESSURES  OF  8f"  O.D.  TUBES  OBTAINED  BY  USE  OF  WeHAGE’S 
Formula,  with  values  based  on  tests  on  National  Tube  Co.’s  Besse- 
mer Steel  Lap-welded  Tubes. 

Broken  lines  show  values  obtained  by  use  of  Weliage’s  Formula  for  welded 
or  butt-joints,  from  Reuleaux’s  Constructor  translated  by  Suplee,  1893,  page 
269.  The  full  lines  show  values  based  on  Prof.  Stewart’s  experiments. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  59 


actual  use  and  in  boilers  under  known  pressures, 
formula  was 


, = f (52g“  - 500) 


The  resulting 
...  (A) 


For  the  collapsing  pressure  of  plain  riveted  boiler  flues,  Clark 
gives  the  following  formula : 


200,000  t2 

P - dl.-,5 


(B) 


For  a comparison  of  values  from  these  formulae  with  the  prob- 
able collapsing  pressures  of  lap-welded  tubes,  see  Fig.  29  and 
column  20  of  Fig.  22. 

Love's  Formula . — M.  Love’s  formula,  which  was  also  deduced 
from  Fairbairn’s  experiments,  is  as  follows : 

p = 5,358,000  ^ + 41,900  -j  + 1,320 


For  a comparison  of  values  obtained  by  its  use  with  the  collaps- 
ing pressures  of  modern  tubes,  see  Fig.  30  and  column  22  of 
Fig.  22. 

Belpaire's  Formula . — From  Fairbairn’s  experiments  Belpaire 
has  deduced  the  following  formula : 

p = 3,427,000  ^ + 56,890,000 

For  a comparison  of  values  from  this  formula  with  the  probable 
collapsing  pressures  of  modern  tubes,  see  Fig.  31  and  column  24 
of  Fig.  22. 

Dr.  Wehage  deduced  a formula  for  flues  with  butt-joints 
which  he  states  is  also  applicable  to  lap-welded  tubes.  This  for- 
mula was  apparently  based  upon  Fairbairn’s  three  experiments 
on  tubes  thicker  than  -J  inch  together  with  three  isolated  tests 
on  boiler  flues  and  two  failures  of  flues  while  in  service. 

In  metric  units,  as  published  in  Dingler’s  Journal,  vol.  242, 
1881,  page  236,  and  in  the  4th  German  ed.  of  Beuleaux’s  Con- 
structor, this  formula  is — 

S 

aL  = 120,000  -g 

where  the  collapsing  pressure,  a1,  is  expressed  in  kilograms  per  sq. 


60  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


centimeter ; while  the  diameter,  D , the  thickness,  S,  and  length  l, 
are  in  millimeters. 

Reduced  to  the  same  British  units  in  which  the  other  formulae 
are  expressed,  this  formula  becomes 

p = 253,600  2\J x2' 

A comparison  of  values  obtained  by  use  of  this  formula  with  the 
results  of  the  present  research  is  shown  in  Fig.  32  and  in  column 
18  of  Fig.  22. 

Suplee’s  translation  of  Reuleaux’s  Constructor,  1893,  page  269, 
states  this  formula  in  British  units  to  be 

^ = 490,000 

For  a comparison  of  results  by  this  formula  with  the  ’-esults 
of  the  present  research  see  column  16  of  Fig.  22,  and  also  Fig.  33. 

English  Board  of  Trade  s Formula,  —The  following  formula 
from  the  English  Board  of  Trade  is  rbtained  from  Fairbairn’s  ap- 
proximate formula  by  using  a factor  of  safety  of  about  9,  and 
substituting  L -f-  1 for  L,  namely. 

_ 90,000  t2 
P ~ (Z  + l)<f 

In  column  26  of  Fig.  22  will  be  found  a comparison  of  values 
from  this  formula  with  the  collapsing  pressures  of  lap-welded 
tubes.  It  will  be  seen  from  an  inspection  of  column  26  that  the 
actual  factor  of  safety,  resulting  from  the  application  of  this 
formula  for  the  assumed  conditions,  varies  approximately  from 
8 to  36. 

Collapsing  Tests,  Series  Two,  on  Twenty-foot  Lengths, 
Showing  the  Influence  of  Diameter  and  Thick- 
ness of  Wall  on  the  Collapsing  Pressure. 

The  purpose  of  Series  One  was  to  determine  the  precise  nature 
of  the  influence  of  length  of  tube  upon  the  collapsing  pressure. 
By  length  of  tube  is  here  meant  the  distance  between  couplings,  or 
other  end  connections,  of  a single  length  of  tube,  tending  to  hold 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  61 

it  to  a circular  form.  The  experimental  determinations  constitut- 
ing Series  One,  as  recorded  elsewhere  in  this  paper,  see  page  26 
and  Fig.  21,  show  conclusively  that  for  commercial  wrought  tubes 
8f  inches  outside  diameter,  there  is  no  practical  difference  in  the 
collapsing  pressure  for  lengths  greater  than  six  diameters  up  to 
twenty  feet.  As  soon  as  this  point  had  been  fully  established  ex- 
perimentally it  was  decided  to  make  all  succeeding  tests  on  tubes 
in  lengths  of  20  feet.  This  was  accordingly  done,  the  results  of 
these  tests  being  grouped  as  Series  Two. 

The  apparatus  used , and  the  manner  of  making  the  tests  of 
Series  Two  were,  in  every  essential  respect,  precisely  the  same  as 
for  Series  One.  A complete  detailed  statement  of  these  will  be 
found  in  that  portion  of  this  paper  that  deals  with  Series  One. 

The  tabular  statement  of  principal  results  of  Series  Two  will  be 
found  in  Figs.  34  to  42.  This  tabular  statement  is  presented  in 
exactly  the  same  form  as  that  of  Series  One.  For  the  precise  mean- 
ing of  the  different  entries  in  this  table,  see  the  explanation  of  the 
entries  of  the  corresponding  table  of  Series  One. 

Derivation  of  Formula  for  the  Probable  Collapsing 
Pressure  of  Lap-welded  Bessemer  Steel  Tubes  for 
Lengths  of  Twenty  Feet. 

Re-grouping  of  Tests. — The  first  step  taken  toward  the  deriva- 
tion of  formulae  for  the  strength  of  wrought  tubes  subjected  to 
external  fluid  pressure,  as  based  upon  the  results  of  the  present  re- 
search, was  the  re-grouping  of  the  tests  as  shown  in  Figs.  43-46. 

This  table  contains  an  abstract  from  the  Log  of  the  results  of 
all  tests  on  tubes  in  lengths  of  20  feet,  excepting  those  that  were 
intentionally  dinged  or  put  out  of  round,  before  being  tested,  for 
the  purpose  of  obtaining  data  on  the  results  of  such  defects. 

It  will  be  observed  that  the  tests  in  this  table  are  grouped  ac- 
cording to  the  outside  diameter  of  tube  and,  for  each  diameter, 
are  arranged  in  the  order  of  thickness  of  wall. 

Plotting  Group  Averages  to  — It  is  apparent  that  for  tubes 

subjected  to  external  fluid  pressure  there  are  three  principal  vari- 
ables involved,  namely,  the  outside  diameter,  d , the  thickness  of 
wall,  t,  and  the  fluid-collapsing  pressure,  P.  It  is  also  apparent 
that  each  of  these  variables  is  a function  of  the  other  two,  that  is 
to  say,  depends  jointly  upon  each  of  them  for  its  value. 


62  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


COLLAPSING  PRESSURES. — Abstract  from  Log  of  Tests  Conducted  by 
Prof  R.T.  Stewart,  /90Z- 04-,  on  National  Tube  Co’s  Lap-welded  Bessemer 
Steel  Tubes,  20  Foot  Lengths,  to  which  is  added  a Comparison  with 
Calculated  Values,  by  Formulae  AbB.  node  by  e.e.s.  under  direction  of  h.t.s.,  I’tos. 


rests  Grouped  according  to  Outside  Diameter  and  Arranged  in  Order  of-  Thickness  ej  of  Tubes. 


Number 

of  Toot 

Outside  Diameter, 
incites. 

Thickness  of  V/all. 
Inches. 

Actual 
P/ain  Ena 
Weight, 
UoS.ptr  Ft. 

Col /op 
Po  un  ds 

sing  Pressure 

per  Square  inch 

Commercial  Designation 

Of  Tube,  as  Reported. 

Nominal 

Actual 

Nomina/ 

Computed 
from  Wgt 

Otser  ved 

Co  ic'd  by 
Formula. 

Variation 
from  Co/caf 

4Xt 

2.777 

0. 107 

0.//0 

3.40 

/S50 

1773 

-Z3.6 

3 Standard  Boiler  Tubing,  3.35* 

4XZ 

3.006 

0.  / 07 

0.//O 

3.40 

/ 630. 

/ 7V  6 

- Sf  7 

m Of  oo 

073 

3.00/ 

0./07 

o.no 

3.40 

1725 

/77t 

- 3.7 

am  oo  oo  of. 

404 

2.773 

0./J7 

O.lll 

3.43 

2025 

6X2V 

4/0.5 

„ .a  oo  oo  ot 

4V7 

3.000 

2.777 

0./20 

O.H  2 

3.45 

/7(0 

/VSl 

4 5.  V 

• .Locomotive.  ” " 3.C5* 

403 

2.776 

0./20 

0.1  /z 

3.45 

/i '00 

/V6S 

- 3.5 

V " " 

urc 

2.777 

0/  20 

0. 112 

3.4S 

/VSO 

/VS  3 

- 0.2 

» " * - " 

407 

2.772 

0./20 

0.//3 

3.4V 

2/75 

/%V  7 

4/5.3 

" //  4/  U ft 

'4?t 

2.77T 

0./20 

0. 114 

3.53 

2025 

n/o 

4 6.0 

00  ,0  00  ,0  „ 

Average 

2.777 

0.  !/2 

344 

/ X60 

/S4/ 

4 0.7 

47/ 

3.000 

2.7X7 

0./5 

0./37 

4.23 

2575 

2647 

- 2.7 

3" Special,  4.57  tbs. 

470 

2.777 

0. 147 

3350 

2V6S 

4/6.7 

Average 

2.472 

0./43 

4.35 

2 762 

2756 

4 7./ 

47  V 

3.000 

0./V2 

5.4V 

3700 

3V72 

- 4.4 

477 

2.774 

0./X7 

S.6S 

4200 

40X3 

4 Z.V 

475 

3.000 

2.770 

o./t 

0./70 

5.6V 

4200 

4/22 

4 /.? 

3' Special.  5.42  lbs: 

47  7 

2.777 

0/70 

5.6V 

4175 

4/07 

4 /.4 i 

476 

2.776 

0./7/ 

5.73 

4200 

4/40 

4 /.S 

Average 

2.795 

o.nsv 

5.64 

4075 

4066 

4 0.7 

414 

3.772 

0.//4 

4.7/ 

X60 

/0V7 

-2/.0 

460 

3.770 

0.//7 

4.7/ 

725 

//77 

-22.V 

463 

4.000 

4.00/ 

O./20 

0./20 

4.7  V 

/030 

/Z/4 

-/S.Z 

4“ Converse  Joint,  4.V7  lbs. 

46/ 

3.770 

0. 122 

5,06 

773 

/Z64 

-22.7 

46Z 

3.770 

0./Z2 

5.03 

/030 

U64 

-/V.S 

Average 

3.773 

0.//9 

4.74 

764 

120  6 

-ZO./ 

467 

4.0/7 

0./67 

6.74 

2/60 

226/ 

- 4.5 

46  f 

4.0/0 

0.173 

7.0  V 

2050 

2333 

-12.7 

467 

4.000 

4.0/2 

O./S 

0./73 

7.// 

2425 

235/ 

4 3./ 

3%t  English,  7.35  lbs. 

466 

4.0/4 

0.17V 

7.2V 

222S 

2457 

- 9.4 

46V 

4.0 /V 

0./V4 

7.53 

2540 

2SV3 

- /.7 

Average 

4.0/4 

0./7S 

7./7 

22V0 

240/ 

- S./ 

474 

4.0/7 

0.205 

t.32 

3075 

3035 

4 /.3 

47Z 

4.027 

0.2/0 

V.S7 

3/50 

3/32 

4 0.6 

47/ 

4.000 

4.024 

0.226 

6.2/3 

V.67 

3/25 

3202 

- 2.4 

3'/f  Full  Weight,  7.00  tbs. 

470 

4.027 

0.2/5 

V.7  7 

3/25 

3237 

- 3.5 

473 

4.02V 

0.2/7 

V.i (2 

3375 

32X3 

4 2.V 

Average 

4.026 

0.2/2 

V.63 

3/70 

3/7V 

- 0.2 

4 7 5 

4.020 

0.324 

/2.77 

5525 

5600 

- /.3 

47  V 

4.0/ / 

0.326 

/2.VS 

5600 

5637 

- /.0 

477 

4.000 

4.0/6 

0.32/ 

0.326 

/Z.VS 

5625 

St  50 

• 0.4 

3/i  Extra  Strong,  12.47  /bs. 

477 

4.0/0 

0.32V 

/ Z.V7 

5425 

3704 

- 4.7 

476 

4.0/2 

0.332 

/ 3.0  5 

5625 

5706 

- z.v 

Average 

4.0/4 

0.327 

/2.V7 

5560 

J6V0 

- 2./ 

ZOO 

6.0/ V 

0./23 

7.77 

450 

424 

4 6./ 

zo/ 

6.026 

0./27 

V.00 

500 

462 

4 V .2 

207 

6.0/6 

O./ZV 

t.07 

4V5 

475 

4 2./ 

206  ' 

6.02/ 

0./Z7 

V./2 

4V0 

4V5 

- /.0 

2 03 

6.000 

6.0/7 

6).  134 

0. 130 

V./7 

540 

476 

4 V.7 

6 " Converse  Joint.  V.26  tbs. 

2 02 

6.0/5 

0/30 

V.I7 

575 

47V 

4/5.5 

204 

6.0/0 

0/3/ 

X.24 

530 

5H 

4 3.7 

205 

6.023 

0/3/ 

V .22 

530 

507 

4 4.5 

207 

6.0/3 

0./34 

3.45 

640 

547 

417.0 

20t 

6.0/3 

0./35 

V .45 

5/0 

360 

- V.7 

Average 

6.0/ 7 

0/30 

V./7 

524 

47  7 

4 5.6 

/ 

2 

3 

4 

5 

6 

7 

X 

7 

JO 

Fig.  43. 


COI  LAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  63 


COLLAPSING  PRESSURES. Abstract  from  Loq  of  Tests  Conducted  by 

ProC  R.  T.  Stewart,  /30Z-O4,  on  National  Tube  Co.'s  Lap-welded  Be  sse  mer 
Steel  Tubes,  ZQ  Foot  Lengths,  to  which  is  added  a Comparison  with 
Calculated  Values,  by  Formulae  AbB.  Mode  by  c.c.s.under  direction  of  R.r.s.,nos. 

7&S/S  Grouped  according  to  Outside  Diameter  and  Arranged  in  Order  of  Thick  nes  ici  of  Tubes. 


Outside  Diameter. 

Thickness  of  Wa/i. 

Actual 

Collapsing  Pressure 

Number 

tncAes. 

/nckee. 

Plain  End 

Pounds 

per  Sguc 

fnch. 

Commercial  Design  ot/on 

of  Test 

Nominal. 

Computed 

Weight, 

Observed. 

CaJc'd  t>y  1 ^Variation. 

of  Tube,  as  Reported. 

from  Wgt 

Lbs. Ft 

Formula. 

from  Gated. 

2U 

2.02V 

0. 152 

0./55 

7.75 

760 

V73 

- 9.V 

Cosing,  tO.*tl  tbs. 

222 

2.037 

0./52 

0./56 

7.79 

YVO 

VSV 

t 3./ 

..  u •• 

2/3 

2.037 

0./52 

0./67 

10.30 

SS6 

76V 

~/Z.Z 

'•  A*  •«  <• 

227 

2.022 

0 .156 

0./66 

/ 0.70 

mo 

/002 

+ /0.V 

M St  <*  '«#. 

22S 

2.03V 

0./S6 

0. 166 

16.37 

7/5 

797 

- 2 V.  3 

II  II  M M 

22/ 

2.637 

0./56 

0. 166 

10.70 

760 

97V 

-23.V 

M «•  H •< 

2/2 

2. 0/  / 

0./S6 

0. 166 

/ 0.35 

750 

ZOOS' 

- 5.V 

1*  II  ••  it 

2/7 

2.02/ 

0./S6 

0./66 

70.37 

7V0 

/ 003 

~ Z.3 

M M II  tS 

2/0 

2.000 

2.007 

0 .152 

0./67 

10.77 

/ 025 

/02V 

+ 0./ 

• • M II  M 

23V 

2.037 

0 .152 

0.167 

/ 0.75 

775 

/on 

-23.3 

«•  M II  M 

27/ 

2.037 

0/52 

0./6V 

/ 0.50 

/OSO 

/027 

/ 2.2 

II  II  II  .« 

2/t 

2.00V 

0.152 

0./6V 

/O.SO 

V60 

/ 037 

-/  7.  / 

• I II  U II 

2/S 

2.033 

0./S2 

O.UV 

/ O.JS 

to/o 

/02V 

• 1.7 

.1  1 M II 

2// 

2.027 

0./S6 

6. 167 

/ 6.57 

730 

7076 

-//./ 

*«  (l  |i  M 

223 

2.022 

0./5C 

0./67 

10.57 

/070 

7075 

f 2.7 

• 1 M II  U 

2*3 

2.037 

0.220 

0/70 

10.62 

V75 

. i 056 

-77./ 

•«  ••  IH.Z6  » 

2/7 

2.03/ 

0. 152 

0.171 

10.67 

/ 096 

107/ 

+ t.r 

••  '*  /O.HG  " 

2/7 

2.03V 

0./S2 

0./7S 

10.72 

1010 

/ 126 

-/0.3 

Average 

2.02  V 

0./67 

10.72 

92V 

/OOV 

- 7.9 

220 

2.02V 

0 . 152 

0./7V 

U./7 

/72S 

/ 173 

72/.  S 

sf  Casing,  10.76  lbs. 

2*0 

2.055 

0.220 

0./79 

n.22 

/o/o 

1176 

-77./ 

••  ••  17.26  *' 

Z70 

2.035 

0.220 

0./77 

//./? 

/ 095 

//VS 

-7.6 

257 

2.027 

0.203 

0JV2 

/ / .35 

/ too 

7233 

-/ O.V 

••  /2X07  •• 

zsr 

2.0/3 

0.203 

0./V2 

/ 1.36 

/3S0 

1237 

+ 9/ 

••  ••  «•  a 

253 

2.020 

0.203 

0./V7 

/ /.75 

9 56 

/ 263 

-27.  V 

I.  ••  •* 

272 

2.000 

2.035 

0:220 

O./VS 

n.s7 

1272 

127/ 

to./ 

«•  ••  IH.19  M 

256 

2.02/ 

0.203 

0./V5 

//.ss 

/ 750 

1277 

t/3.5 

••  tZ.C't  M 

25  7 

2.025 

0.203 

0./V7 

11.77 

1256 

7333 

- £.2 

.1  .1 

255 

2.02  V 

0.20  3 

0./72 

/1.7V 

790 

7 37S 

-72.5 

II  1.  1. 

250 

2.0/2 

0.203 

0. 172 

t/,76 

/ 750 

/3V6 

t S.7 

II*  •#  II  (1 

275 

2.0/0 

0.220 

0./73 

/ / .77 

7375 

/377 

- /.6 

..  ..  W.IQ  •• 

277 

5.77V 

0.220 

0./73 

/ / .77 

1750 

/703 

717.7 

.. 

Average 

2.027 

0. 176 

H.57 

iZS! 

/ZVS 

- 2.6 

25/ 

2.0/2 

0.203 

0.2/7 

13.25 

/7S0 

/ 677 

t 3./ 

Sf" Casing,  /z.67  tbs. 

27/ 

2.021 

0.220 

0.2/7 

13.57 

/ 606 

1767 

- 9.7 

••  « /7.20  •• 

257 

2.005 

0.203 

0.220 

13.57 

/5S0 

nv9 

-73.7 

..  ..  /2.07  •• 

252 

2.000 

2.020 

0.203 

0.222 

13.73 

2675 

/V/0 

f/7.6 

•• 

*277 

2.032 

0.220 

0.22V 

17.15 

/ZOO 

/VVV 

- 36.7 

••  ••  17.20  » 

272 

2.00/ 

0.220 

0.230 

/7./7 

/700 

1736 

- 7.9 

27V 

2.067 

0.220 

0.232 

17.30 

/VO  6 

/963 

- t.3 

Average 

£.0// 

0.222 

13.77 

1779 

/VZ7 

- 2 5 

* Defective,  not  in  averages. 

7/5 

2.072 

0.27/ 

0.250 

15.53 

2220 

2/V3 

t /.7 

Jf"  Cosing , 16.70  ibs. 

2 2/ 

2.027 

0.27/ 

0.25/ 

15.77 

/ 750 

2ZZ3 

-Z/.3 

177 

2.072 

0.27/ 

0.257 

15.77 

2360 

2Z70 

t S.7 

272 

2.033 

0.27/ 

0.257 

15.77 

2775 

2335 

t 6. 0 

* 220 

2.057 

0.27/ 

0.260 

16.06 

1755 

2336 

-27.9 

.. 

227 

2.022 

0.27/ 

0.260 

15.77 

2750 

2356 

+ 7.0 

7/2 

2.072 

0 27/ 

0.262 

16.16 

2555 

237Z 

t 7.7 

..  V 

f22Z 

6.033 

0.27/ 

0.26  3 

16.20 

2600t 

2392 

t V.7 

2X2 

2.027 

0.27/ 

0.267 

/ 6.77 

2250 

2756 

- V.7 

772 

2.000 

5.770 

0.27 

0.267 

16.75 

2590 

Z506 

t 3.7 

6 ' O.D.  Special , tl./X  the. 

77/ 

5.773 

0.2  V 

0.267 

16.75 

2/50 

2507 

-17.1 

27  3 

2.02/ 

0.27/ 

0.270 

16.59 

2270 

250/ 

- <7.2 

S-a  Casing , 16.10  ibs. 

its 

£.022 

0.27/ 

0.Z76 

16.55 

2550 

2500 

+ 20 

773 

5.77X 

0.2V 

0.27/ 

/ 6.55 

2760 

2530 

- 2.V 

6"  O.D.  Special , n./Z  /bs. 

7/7 

£.072 

0.27/ 

0.27/ 

16.71 

2700 

250/ 

- 7.0 

5§‘  Casing,  16.16  / bs  . 

7/7 

2.077 

0.27/ 

0.27/ 

16.73 

2575 

2500 

/ 3.0 

770 

5.77/ 

0.27 

0.273 

/ 6.6V 

27X0 

2563 

+ V.5 

6"  0.0.  Special , /T.tZ/bs. 

777 

5.773 

O.ZV 

0.277 

16.73 

2755 

2576 

- 7.7 

..  ..  ;.  ..  ..  ^ 

7/X 

2.077 

0.2  7/ 

0.277 

/7.6V 

2V70 

ISVi 

+ //.V 

■5§"  Casi  ng ./ 6.1 0 /bs. 

223 

2.025 

0.27/ 

0.2V6 

17.17 

2600 

267 Z 

- 1.6 

” 

Average 

£022 

0.266 

/6  3V 

247/ 

2776 

- O.Z 

Defective,  not  tn  averages. 

? Did  not  co/taps e. 

/ 

2 

3 

4 

S' 

6 

7 

9 

7 

IO 

Fig.  44. 


64  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


COLLAPSING  PRESSURES. — Abstract  from  Log  of  Tests  Conducted  by 
Prof  R.T.  Stewart,  I30Z-64,  on  National  Tube  Co.’s  Lap-welded  Bessemer 
Steel  Tubes,  20  Foot  Lengths,  to  which  is  added  a Com parison  with 
Calculated  Values,  loy  Formulae  A&B.  Made  by  e.e.s.  under  direction  of  r.t. s.,  nos. 

Tests  Grouped  according  to  Outside  Diameter  and  Arranged  in  Order  of  Thicknesses  of  Tubes. 


Number 

of  Test. 

Outside,  Diameter 

fn  cbes. 

Thickness  of  VJaii, 
In  c htt  j. 

Actual 
Plain  End 
Weight, 

Lbs.p*rFt. 

Collapsing  Pressure 

Pounds  per  Square,  inch. 

Commercial  Designation 

Of  Tube,  as  Reported. 

Nomina/ 

Actual 

Nomina/ 

Computed 
from  Wgt. 

Observed 

Calc'd  by 
Formula. 

% Variation 

from  Cok'd 

0.005 

O./S 

3/ 52 

13.57 

5*5 

59/ 

- /.6 

6 §"  O.D.  Special,  13.39  lbs. 

hoh 

0057 

a./s 

0/53 

/ 0.S9 

520 

606 

-19.2 

HO  3 

i.ilS 

0.00/ 

3. IS 

0./5H 

/ 3.07 

563 

67X 

- 9.H 

*900 

£.003 

3./  5 

3.  / 5H 

/6.0X 

H33 

6/7 

-35.1 

3 16 

£.£S7 

0./72 

3. 157 

/ 0. *7 

7/0 

CSX 

- 7.9 

6+"  Casing,  II. 5*  tbs. 

HOI 

£.£Str 

3.  !5 

6.  IS7 

/ 0.  *7 

5*5 

OSX 

-//./ 

Of  O.D.  Special,  10.39  lbs. 

A veroge 

£.000 

3./5S 

/ 0.7 i 

59  2 

026 

- X.7 

* Defective , not  in  averages.  See  tog. 

303 

£.053 

3/ OH 

II  .35 

733 

753 

- 2.7 

3 OH 

£.025 

0.052 

3.172 

a. /os 

U .HZ 

030 

70H 

-2/.S 

6 f Casing,  n.sx/bs. 

30/ 

0.057 

0./05 

II.H7 

7 23 

76Z 

- 5.5 

301 

0.053 

O./CX 

/ 1.02 

030 

X 33 

-2/.  5 

Average 

O.OSH 

3.760 

/■/  .H7 

07  0 

770 

-/2.X 

3 OS 

0.0X0 

0.176 

/3.S7 

7/00 

7 157 

- H.9 

30? 

£.070 

0./90 

i 3.57 

1375 

US 9 

-9.2 

300 

0.025 

0.093 

3.233 

3.233 

/ 33/5 

/Z05 

/Z09 

HO./ 

of  Casing,  13.32  tbs. 

307 

0.0*2 

0.232 

/ 3.7 9 

1275 

/Z3H 

F 3.3 

30 * 

0.0*7 

3.235 

/H./7 

/ZOS 

1271 

- 3.5 

Average 

0.0*9 

0.200 

73X3 

77*9 

HOS 

-/.* 

HI  0 

o.cvo 

O.ZH/ 

/0.S9 

7 6*3 

/73X 

- 3.3 

HI3 

0.0  79 

3.ZHX 

10.79 

/7/0 

7X32 

- 6.7 

H/H 

0.0*2 

3.2HX 

17.0/ 

/6/S 

7X37 

-//.S' 

* 3/3 

0.057 

6.250 

/7.D? 

1*20 

7X69 

- 2.6 

3IH 

£.025 

0.07 / 

3.23 r 

3.25/ 

17.20 

2/75 

1X75 

-t/6.0 

6f  'casing , 17.02  tbs. 

HU 

0.0* H 

3.25/ 

/7.2H 

!9  HO 

7X69 

F 3* 

3/2 

0.009 

0.252 

t 7.25 

1975 

7XX9 

F 9.0 

3/1 

0.07H 

0.2SH 

77.3? 

2/60 

79/3 

7/2.9 

HIZ 

0.075 

3. 2 SO 

I7.SI 

17*6 

193* 

- X.  2 

Average 

0.077 

3.253 

17.15 

/V79 

7X0l 

t 0.9 

*lron.  not  in  averages. 

310 

0.00/ 

3.23 X 

3.203 

/7.7V 

2275 

7997 

7/3.9 

6+  Casing,  17.02  tbs. 

HO* 

0.0  5/ 

0.2X3 

3.20/ 

I7.XI 

2303 

23/5 

F 2.2 

6 " Full  Weight,  /V.  76  lbs. 

HOS 

0.025 

o.ose 

3.2*3 

0.202 

/7.X  5 

2/35 

232 X 

F 5.3 

.. 

H30 

0.053 

3.2*3 

0.202 

/7.X  5 

/ 9 75 

2327 

- 2.0 

»• 

H 07 

0.055 

0.2*0 

3.27X 

72.99 

2560 

2239 

F/H.6 

..  .# 

HO 9 

O.OSH 

0.2*0 

3.2XH 

19.35 

2393 

2313 

F / .2 

Average 

0.052 

3.2£* 

/V.26 

222V 

2/02 

7-  5.*r 

H39 

7.539 

0./9X 

3. 153 

/ / .2/ 

S/S 

5/3 

F 3.9 

7"  Converse  Joint,  /e.os  lbs. 

3/7 

7.393 

O./XO 

3./5H 

11.31 

5 75 

5/5 

F//.0 

Off  Casing,  / 2.3H  lbs . 

H37 

7.369 

O./HX 

O./SS 

/ / .3/ 

6 35 

533 

F/3.5 

7"  Converse  Joint,  /e. OS  lbs. 

3/0 

7.  OHO 

O./XO 

o./si 

/I.SX 

550 

559 

- /.0 

6§~  Casing,  12.39  tbs. 

3/S 

7.000 

7.0HC 

O./XO 

6./5X 

11.01 

570 

55* 

F 2.2 

H3S 

7.00 * 

O./HX 

0/0/ 

n .75 

£65 

6 0S 

F 9.9 

7 Converse  Joint,  to. 05  tbs. 

H3X 

7.6/5 

O./HX 

6./02 

U.X5 

£75 

0/5 

F 9.X 

..  ..  ,.  ..  .. 

3/9 

7.05 9 

O./XO 

3. 103 

H.70 

593 

675 

-I2.2 

Of'Casing , 12.39  tbs. 

3/r 

7.333 

6./X0 

O./OO 

U./3 

5*3 

003 

-12.1 

H3i 

7.3/5 

0.  !HX 

0./6X 

/ 2.25 

CHS 

690 

- 0.5 

7 Converse  Joint , 10.65  tbs. 

Average 

7.32* 

0./60 

/ / .70 

592. 

3X6 

F /.  5 

322 

7.3  57 

0.233 

70.97 

1525 

7976 

F 3.3 

32/ 

7.050 

6.ZHI 

n.so 

1575 

7577 

- 3./ 

320 

7.000 

7.0  S3 

0.2HX 

6.ZHS 

17.70 

1775 

1626 

F 9.2 

0-f  Casing,  17.51  tbs. 

323 

7.3H5 

0.2  H 5 

n.77 

U75 

162 * 

F 2.9 

32H 

7.3H7 

0.2HX 

/X.02 

7X53 

7669 

F//.2 

Average 

7.353 

3.292 

n.oo 

76X0 

7599 

F S3 

H3Z 

7.3/* 

0.20* 

79.33 

7*35 

7929 

- H.O 

H3H 

0.9*H 

3.209 

19. 3H 

1975 

7 952 

7 / .2 

H3/ 

7.000 

0.975 

3.2X 

3.2X3 

23.23 

2300 

2/30 

7 X.O 

7 O.D.  Special . 2.0.12  lbs. 

H33 

0.97H 

3.1X7 

Z3.H7 

Z/X6 

21*1 

- 0.0 

H30 

0.9X9 

3.290 

23.7H 

2995 

22/3 

7/3.5 

A veroge 

6.9*7 

0. 279 

10.02 

2JH7 

20*3 

F 3.3 

) 

2 

3 

A 

5 

£ 

7 

8 

9 

70 

Fig.  45, 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  65 


COLLAPSING  PRESSURES. — Abstract  from  Log  of  Tests  Conducted  by 
Prof  R.  T.  Stewart,  /902-04,  on  National  Tube  Co.'s  Lap-welded  Bessemer 
Steel  Tubes,  20  Foot  Len qths,  to  which  is  a d d ed  a Com parison  with 


Calculated  Values,  by  Formulae  A&B.  Made  by  e.l. 5.  under  direction  of  r. r. s.,  /90s. 

Tests  Grouped  according  to  Outside  Diameter  and  Arranged  in  Order  of  Thickness  es  of  Tubes. 


Humber 

of  Test 

Outside  Diameter; 
/netted. 

Thickness  of  Via//, 
inch  as. 

Actual 

P/ainEnd 

CoJ/ap 

Po  u n c/s 

sing  Pressure., 

per-  Square.  fnc,h. 

Commercial  D KSignation 
of  Tube,  as  Reported. 

Nomina/. 

Actual. 

Nominal 

Computed 
from  Wqt. 

Weight, 

L6s.pT  ft 

Observed 

Ca/c'd  by 
Formula. 

%1/ar/otion 
from  Calc'cL 

/ 

f.657 

6.  / 7( 

/S.92 

956 

9/ y 

f 7.7 

9 

7.696 

6/73 

/ (.51 

950 

9(1 

- 9.6 

3 

? .625 

7.69! 

O. 170 

0./7( 

/ 6.77 

535 

91/ 

9 9.0 

?F  Casing,  7 (.07  lbs. 

2 

7.637 

6.  m 

n.zi 

625 

539 

9/7.6 

S 

7.637 

6./1/ 

7 7.23 

(26 

533 

9/0.3 

Averaqe 

7.613 

6/75 

76.79 

536 

971 

9 1.2 

26 

? .625 

7.661 

0.221 

6.2/1 

11.57 

776 

126 

9 6.1 

i 'ff  Casing,  26. /0  lbs. 

£2 

7.661 

0.27/ 

6.257 

23.13 

/320 

7/95 

9/6.5 

l£" Casing,  29.31  7bs. 

51 

7.666 

6.27/ 

6.2(2 

23.52 

7975 

72'3( 

920.7 

95 

7.663 

6.322 

6.2(9 

13.6( 

7375 

7255 

9 1C 

1 L i ne  Pipe.,  27.  H lbs. 

Si 

7.660 

6.27/ 

6.27/ 

29.27 

7935 

7326 

9 1.2 

If  Casing,  29.3?  lbs. 

S3 

? .625 

7.666 

6.27/ 

6.Z72 

29.32 

7526 

7336 

9/3.7 

70 

7.(63 

6.27/ 

6.272 

29.31 

IHIO 

7335 

9 3.6 

1"  Line  Pipe , 25.06  tbs. 

75 

7.610 

0.27/ 

0.279 

29.99 

7375 

73(3 

9 0.9 

5/ 

7.667 

6.7.7/ 

6.279 

29.59 

/*t30 

7359 

9 S.C 

?jf  Casing,  29.31  ibs. 

*77 

7.666 

4.  2*7 

0.279 

29.97 

1275 

7356 

-6.0 

1"  Line  Pipe,  25.66  lbs. 

*77 

7.666 

6.27/ 

0.270 

25.61 

1256 

79/ C 

-II.  7 

Average 

7.666 

6.2(7 

29.03 

/-y/9 

7366 

9 1. 3 

*lror>,  not  in  averages, 

7 0 / 

7.697 

6.322 

0.219 

26.2  7 

7(56 

756/ 

9 5.7 

?"  Line  Pipe,  21.71  7bs. 

106 

7.696 

6.322 

6.217 

26.11 

77/0 

1591 

9 7.5 

111 

7.671 

6.322 

6.362 

2C.11 

7575 

7(33 

- 3.5 

1"  Full  Weight,  27.71  7bS. 

IOZ 

7.656 

6.322 

6.363 

27.66 

71(6 

7(97 

971.1 

7"  Line  pipe,  Zl./t  ibs. 

923 

7.625 

7.691 

6.322 

6.363 

2 7.66 

7736 

7(50 

970.1 

1"  Full  Weight,  21. /?  Ibs. 

92! 

7.666 

6.322 

6.363 

27.61 

7 935 

7(99 

977.  7 

« 

922 

7.672 

6.322 

6.367 

27.31 

7(35 

7(12 

- 2.1 

tn 

7.666 

6.322 

6.361 

27.99 

7735 

7(99 

9 2.9 

ST"  Line  Pipe.  21. H tbS. 

926 

7.(57 

6.322 

6.3/6 

27.(9 

nos 

777  7 

9 S.7 

SC"  Full  Weight.  21. nibs. 

Average. 

7.657 

6.362 

ZC.17 

77(2 

7(1/ 

9 7.9 

T0.  H.  Steel,  not  in  overages. 

*927 

S .677 

6.3K 

36.12 

H36 

2670 

-77.5 

* 925 

7.666 

6.391 

3/.  66 

2/16 

2/69 

9 3.6 

*92? 

s.us 

7.669 

6.3(3 

6.353 

3/.3C 

2695 

2795 

- 9.7 

ST"  Oil  Well  Tubing,  32.66  ibs. 

*921 

7.673 

0.3S6 

31.(2 

1136 

2 7(7 

-t6.1 

*126 

7.672 

6.3(9 

32.36 

2/55 

2252 

- 9.3 

Average 

7.673 

6.359 

3/.9Z 

2627 

2/ 91 

- S.( 

*/ron , group  rejected. 

199 

16.655 

6.157 

/ (.55 

2/0 

2/1 

- 9.1 

997 

10.695 

6./6C 

17.56 

296 

256 

-9.0 

115 

/0.660 

16.637 

6. /St, 

6.UJ 

17.57 

2/6 

259 

-77.3 

/O"  Converse  Joint, /(./? /bs. 

996 

16.631 

6/67 

n.si 

225 

259 

-II.9 

99? 

16.635 

6.  no 

17.91 

296 

2(5 

- 1.9 

Average 

/ 6.69! 

6/(5 

77.93 

225 

291 

- 1.2 

952 

76.665 

6. 175 

/ 1.93 

365 

327 

- 5.7 

953 

76.633 

6./16 

19.11 

315 

397 

9/3.1 

95 1 

16.666 

76.629 

6.263 

6.  Ill 

26.35 

396 

3(7 

9 (3 

Id"  Boi/er  Tu bing,  Z/.66  Ibs . 

951 

16.637 

6/ 15 

20.59 

966 

37/ 

9 7.V 

950 

76.627 

6.26  ( 

2/. 57 

925 

936 

- / .2 

Average 

76.626 

6./19 

26.37 

373 

3(1 

9 9.6 

956 

9.196 

0.3/2 

32.27 

7356 

1321 

9 2 2 

9S9 

70.623 

6.3/9 

32.(1 

7315 

1329 

9 9.2 

957 

16.666 

1.179 

6.30 

6.3/7 

32. 7/ 

7275 

/3C9 

- 6.5 

/O'  O.D.  Special,  3/  67  lbs. 

95 1 

7 6.663 

6.3/7 

32  11 

1365 

13(6 

- 9.6 

955 

76.660 

6.3/1 

33.6/ 

/Z16 

1379 

- 7.2 

Averager 

16.601 

6.3/6 

32.(1 

73/9 

735/ 

- 2.3 

/ 

2 

3 

4 

5 

7 

1 

7 

/ o 

Formula  P , P-  1000  ( 1-Vi-itcoD  J . Formula  3 , P = 36670  j - 13 S 6. 


P%  Collapsing  fluid  pressure,  in  lbs.  per  sq.  in.,  t • thickness  of  trail  In  inches,  d ~ Outside  dia.  of  tube  in  injches. 
Formula  d applies  only  to  values  of  £ greater  than  0.227 , Or  pressures  greater  than  581  pounds / trhUe  for  — 
ipiula  P applies  only  to  Values  less  then  these- 


Fig.  46. 


66  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


After  a fruitless  effort  to  derive  a satisfactory  formula  on  the 
basis  of  three  variables,  which,  when  plotted,  would,  of  course,  be 
a surface  in  space,  the  thought  happily  presented  itself  that  two  of 

these  variables,  t and  d,  could  be  replaced  by  their  quotient,  or  ~ 


which,  of  course,  might  be  treated  as  a single  variable.  By  the 
adoption  of  this  expedient,  matters  were  greatly  simplified,  since 
it  thus  became  possible  to  plot  the  results  of  the  tests  for  all  di- 
ameters and  thicknesses  of  wall  on  a plane  surface. 

Big.  47  shows  the  group  averages  of  Figs.  43-46  plotted  in  this 
manner,  that  is  to  say,  to  a vertical  scale  representing  fluid- 
collapsing pressures  in  pounds  per  square  inch,  and  a horizontal 
scale  representing  the  quotient  arising  from  dividing  the  thickness 
of  wall  by  the  outside  diameter,  both  being  expressed  in  inches. 

Formula  B. — By  an  inspection  of  Fig.  47  it  became  apparent 
that  the  bulk  of  the  group  averages  could  be  represented  by  a 
straight-line  formula,  indeed  all  of  them  could  be  thus  represented 
with  the  exception  of  the  few  having  values  of  thickness  divided 
by  outside  diameter  less  than  0.023.  In  other  words,  about  93 
per  cent,  of  the  group  averages  of  Figs.  43-46  can  be  thus  repre- 
sented. 


On  this  basis  then,  for  values  of  greater  than  0.023,  formula 
B was  deduced,  it  being  as  follows : 


P = 86,670  - 1386  (B) 

Where  P = collapsing  pressure,  lbs.  per  sq.  inch, 
d = outside  diameter  of  tube  in  inches, 
t = thickness  of  wall  in  inches. 


Remembering  that  this  same  formula  might  also  have  been  ar- 
rived at  by  the  substitution  of  proper  empirical  constants  in  a 
similar  formula  for  a theoretically  perfect  tube,  and  further,  since 
Fig.  47  shows  no  apparent  deviation  from  straightness  on  the 
upward  course,  it  was  not  thought  necessary  to  set  an  upper  limit 


to  the  value  of  in  the  application  of  this  formula,  believing 


that  it  will  give  substantially  correct  results  for  all  commercial  lap- 
welded  Bessemer-steel  tubes  whose  thickness  divided  by  the  out- 
side diameter  is  greater  than  0.023. 

Formula  A. — This  formula  for  values  of  -4-  less  than  0.023 

d 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  67 


R.T.  Stewart  "Pulliams  Enz.  Co.,  N.T. 


Fig.  47. — Chart  showing  Actual  and  Calculated  Collapsing  Pressures 
of  National  Tube  Co.'s  Bessemer  Steel  Lap- welded  Tubes  Plotted 
to  Thickness  -t-  Outside  Diameter,  or  %/d . Based  on  Tests  by  Prof 
Stewart  on  20-foot  lengths. 

Note  that  group  averages  are  represented  by  crosses  ( + ),  the  attached 
figures  indicating  outside  diameter,  while  values  calculated  by  means  of  formulae 
A and  B are  represented  by  circles  (O). 


68  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


was  derived  upon  the  assumption  that  when  plotted  upon  Fig.  47 
the  resulting  curve  should  be  tangent  to  the  straight  line  represent- 
ing formula  B,  and  be  also  tangent  to  the  horizontal  axis  at  the 
origin  0.  This  arbitrary  assumption  gave  a formula  which  repre- 
sented very  satisfactorily  the  few  experiments  in  which  ~ was 

CL 

less  than  0.023.  The  formula  thus  obtained  is 


P = 1000^1  - ^/i  _ 1600^  • • • • (A) 


Where  P,  d and  t are  the  same  as  for  formula  B. 


This  formula  should  be  used  for  values  of 
and  for  P greater  than-^j/ ^ 


less  than  0.023 


Since  constructing  the  charts  and  tables  contained  in  this  paper, 
\t  was  discovered  that  a formula  having  a rational  form  with  em- 
uirical  constants  could  be  substituted  for  the  purely  empirical 
formula  A.  This  formula,  in  addition  to  involving  theoretical 
considerations  of  elasticity,  is  much  the  simpler  of  the  two.  It  is 
applicable  only  to  tubes  having  relatively  thin  walls,  that  is  to 

say,  to  those  having  values  of  less  than  0.023,  and  is 

P = 50,2l0,00()Qy (G) 


Where  P } d and  t are  the  same  as  for  formula  A. 

Either  formula  A or  G represents  satisfactorily  the  results  of 
the  experiments  made  on  thin-walled  tubes,  that  is,  those  in  which 

A is  less  than  0.023,  but  probably  formula  G will  permit  of  the 

greater  exterpolation. 

The  following  formulae  are  meant  for  application  in  case  the 
outside  diameter  and  plain-end  weight  are  given.  They  were 
derived  irom  formulae  A and  B and  are 


p = 1000 


^1  - j/ 149.8  ^ - 799  4-  800  |/l  - 0.375  ^.(O) 


41,950  - 26,520  j/  2.67 


(D) 


Where  w = the  plain-end  weight  of  tube  in  pounds  per  foot, 
while  P and  d are  the  same  as  for  formulae  A and  B. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  69 


Formula  C is  lor  values  of  less  than  0.237  and  P less 

az 

than  581  lbs.,  while  formula  D is  for  values  greater  than  these. 

Charts  of  Actual  and  Calculated  Collapsing  Pressures. — 
Figs.  48-50  show  a comparison  of  the  results  obtained  by  actual 
test  with  the  corresponding  calculated  values,  plotted  to  a vertical 
scale  representing  collapsing  pressures  in  pounds  per  square  inch, 
and  a horizontal  scale  representing  the  thickness  of  wall  in 
decimals  of  an  inch.  It  will  he  noted  that  Fig.  48  is  for  the  ex- 
perimental tubes  having  outside  diameters  of  3,  6 and  10  inches, 
the  diameter  being  written  in  each  case  on  the  margin  at  the  right- 
hand  end  of  the  line  representing  the  tube.  Similarly,  Figs.  49 
and  50  were  constructed  for  the  tubes  having  outside  diameters  of 
respectively  4 and  7 inches,  and  6f  and  8f  inches. 

The  lines  on  these  Charts  were  plotted  from  values  calculated 
by  means  of  formulae  A and  B,  representing  the  most  probable 
values  for  the  collapsing  pressures  of  lap-welded  Bessemer-steel 
tubes  in  lengths  of  20  feet  between  transverse  joints  tending  to 
hold  the  tube  to  a circular  form.  The  center  of  each  small  circle 
lying  on  these  lines  represents  a plotted  calculated  value. 

The  actual  collapsing  pressures  of  the  different  tubes  tested, 
plotted  to  the  same  scales  as  the  calculated  values,  are  represented 
by  crosses  (+J  for  those  having  outside  diameters  of  3,  10,  4,  7 
and  8f  inch,  and  by  tees  (T)  for  the  6 and  the  6|  inch.  In  a 
number  of  instances,  in  order  to  avoid  confusion,  the  characters  be- 
ing very  close  together,  it  became  necessary  to  omit  a part  of  the 
cross  (+),  in  which  case  it  became  a tee  (T),  and  likewise  a part 
of  the  tee,  it  thus  appearing  as  an  angle  or  ell  (L). 

Group  averages  are  represented  on  these  charts  by  means  of 
combined  crosses  and  circles  (-o-). 

It  will  be  observed  that  the  group  averages  of  the  actual  collaps- 
ing pressures  lie  very  close  to  the  corresponding  values  calculated 
by  means  of  formulae  A and  B.  For  the  actual  variation  in  per 
cent.,  see  Figs.  43-46,  column  9.  which  gives  the  variation  for  the 
individual  tests  as  well  as  for  the  group  averages. 

Formula?  A and  B being  based  upon  the  results  of  all  the  ex- 
periments on  the  20-foot  lengths  of  the  lap-welded  Bessemer-steel 
tubes  tested,  excepting  the  three  that  proved  to  be  defective,  it  is 
clear  that  the  curves  plotted  on  these  charts  represent  average 
values  for  the  extreme  range  in  thickness  of  wall  for  each  of  the 
seven  diameters  tested. 


70 

6000 

5800 

5600 

5400 

5200 

5000 

4800 

4600 

4400 

4200 

4000 

8800 

3600 

3400 

3200 

3000 

2800 

2600 

2400 

2200 

2000 

1800 

1600 

1400 

1200 

1000 

800 

600 

400 

200 

Fig. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


.02  .04  .06  .08  .10  .12  .14  .16  .18  .20  .22  .24  .26  .28  .30  .32  .34  .36  .38  .40 

r.  Stewart.  Williams  Eng.  Co.  N.Y. 


48. — Chart  showing  Actual  and  Calculated  Collapsing  Pressures 
)f  National  Tube  Co.’s  Bessemer-Steel  Lap-welded  Tubes  Plotted 
ro  Thickness  of  Wall.  For  Outside  Diameters  of  3,  6 and  10 
NCHES,  IN  20-FOOT  LENGTHS.  BASED  ON  TESTS  BY  PROF.  STEWART, 
L902-4. 

ote  that  individual  experiments  are  represented  by  crosses  (+),  calculated 
:s  by  circles  (o),  and  group  averages  by  combined  circles  and  crosses  (-6-) 


3800 

3600 

3400 

3200 

3000 

2800 

2600 

24C0 

2203 

2000 

1800 

1600 

1400 

1200 

1000 

800 

600 

400 

200 

( 

£ 

Fig, 


COLLAPSING  PRESSURES  OF  TAP-WELDED  STEEL  TUBES.  71 


4" 


49. — Chart  showing  Actual  and  Calculated  Collapsing  Pressures 
of  National  Tube  Co.’s  Bessemer-Steel  Lap-welded  Tubes  Plotted 
to  Thickness  of  Wall.  For  Outside  Diameters  of  4 and  -7  inches, 
in  20-foot  lengths.  Based  on  Tests  by  Prof.  Stewart,  1902-4. 
sTote  that  individual  experiments  are  represented  by  crosses  ( + ) calculated 
es  by  circles  (o)  and  group  averages  by  combined  circles  and  crosses(-o-). 


4000 

3800 

3600 

3400 

3200 

3000 

2800 

2600 

2400 

2200 

2000 

1800 

1600 

1400 

1200 

,1000 

800 

600 

400 

200 

C 

li 

'’IG. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


.02  .04  06  .08  .10  .12  .14  .16  .18  .20  .22  .24  .26  .28  .30  .32  .34  36  .38  ,40 

T.  Stewart  Williams  Eng.  Co.,  N.U' 


50. — Chart  showing  Actual  and  Calculated  Collapsing  Pressures 
r National  Tube  Co.’s  Bessemer-Steel  Lap-welded  Tubes  Plotted 
) Thickness  of  Wall.  For  Outside  Diameters  of  6f  and  8f  inches,  in 
l-FOOT  LENGTHS.  BASED  ON  TESTS  BY  PROF.  STEWART,  1902-4. 
te  that  individual  experiments  are  represented  by  crosses  ( + ),  calculated 
by  circles  (o),  and  group  averages  by  combined  circles  and  crosses  (-<>)• 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  73 


The  scattering  of  individual  results  as  compared  with  the  gen- 
eral average  appears,  from  these  charts,  to  be  restricted  to  com- 
paratively small  bounds  when  it  is  considered  that  we  are  dealing 
here  with  a product  that  varies  noticeably  in  a number  of  the 
characteristics  that  go  to  make  up  its  strength.  Since  these  charts 
represent  the  results  of  tests  on  the  common  run  of  commercial 
lap-welded  Bessemer-steel  tubes,  taken  at  random  from  the  stock, 
it  is  surprising  that  the  scattering  of  individual  results  is  not 
greater  than  that  shown. 

Apparent  Fiber  Stress  on  Wall  of  Tube  at  Instant 
of  Collapse. 

Fig.  51  shows  the  apparent  compressive  stress,  in  pounds  per 
square  inch,  at  the  instant  of  collapse,  on  the  walls  of  the  tubes 
constituting  Series  Two.  This  chart  is  constructed  to  a horizontal 
scale  representing  thickness  of  wall  divided  by  outside  diameter 
of  tube  and  a vertical  scale  representing  apparent  fiber  stress  in 
pounds  per  square  inch. 

The  crosses  (+)  represent  the  apparent  fiber  stress  of  the 
group  averages  of  Figs.  43-46,  the  attached  figures  indicating  the 
outside  diameter  of  tube,  while  the  curve  represents  the  formulse  E 
and  F,  plotted  to  the  same  scales.  These  formulae,  which  were 
deduced  to  represent  the  most  probable  values  of  the  apparent  fiber 
stress  in  the  walls  of  the  tubes  constituting  Series  Two,  at  instant 
of  collapse,  are  as  follows : 

For  values  of  4 less  than  0.023 : 

a 

£=500  4(l  _ |/i-  1,600^  . . .(E) 

And  for  values  of  ^ greater  than  0.023  : 

£=  43,335  - 693  f (F) 

Where  8 = apparent  fiber  stress  in  lbs.  per  sq.  inch, 
d — outside  diameter  of  tube  in  inches, 
t = thickness  of  wall  in  inches. 

An  inspection  of  this  chart  will  show  that  the  apparent  fiber 
stress  on  the  wall  of  the  tube  at  instant  of  collapse  varied  all  the 
way  from  about  7,000  pounds  per  square  inch  for  the  relatively 


74  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  51. — Chart  showing  Actual  and  Calculated  Apparent  Fiber  Stress 
on  Wa  l op  Tube  at  Instant  of  Collapse,  Plotted  to  Thickness 
Diameter,  */d  for  National  Tube  Co.'s  Bessemer-Steel  Lap- 
welded  Tubes.  Based  on  tests  on  20-foot  lengths  by  Prof.  Stewart, 
1902-4. 

Note  that  crosses  ( + ) represent  group  averages  of  tests,  the  attached  figures 
indicating  outside  diameters,  while  circles  ( O ) represent  calculated  values. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


75 


thinnest  to  35,000  pounds  per  square  inch  for  the  relatively  thick- 
est walls. 

This  chart  shows  conclusively  that  the  ability  of  a commercial 
wrought  tube  to  withstand  a fluid-collapsing  pressure  is  not  de- 
pendent alone  upon  either  the  ultimate  strength  or  elastic  limit  of 
the  material  constituting  it.  A study  of  this  chart  has  led  to 
some  very  interesting  deductions  which  will  be  dealt  with  in  a 
separate  paper. 

Relation  of  Point  of  Collapse  to  Length  of  Tube. 

Theoretically  a tube  should  begin  to  callapse  at  the  middle 
of  its  length,  that  is,  at  a point  half  way  between  transverse 
joints,  or  end  connections,  tending  to  hold  it  to  a circular  form. 
This  statement  is,  of  course,  based  upon  the  assumption  that  the 
material  of  the  tube  is  perfectly  homogeneous  in  its  physical  prop- 
erties  and  that  the  diameter  and  thickness  of  wall  are  strictly  con- 
stant throughout  its  entire  length. 

The  truth  of  the  above  statement  becomes  apparent  when  we 
consider  that  the  strength  of  a tube  to  resist  collapsing  pressure 
depends  upon,  first,  the  transverse  rigidity  of  its  wall  and,  second, 
the  tendency  of  the  end  connections  to  hold  the  tuDe  to  a circular 
form.  Since  the  former,  for  the  assumptions  made,  would  be  con- 
stant from  end  to  end  of  the  tube  and  since  the  latter  tendency 
would  become  less  as  the  distance  from  an  end  connection  increases, 
it  is  evident  that  a theoretically  perfect  tube  subjected  to  a fluid- 
collapsing pressure  would  be  weakest  at  a point  that  is  at  the  great- 
est possible  distance  from  both  of  its  ends,  which  point  is,  of 
course,  located  at  the  middle  of  its  length. 

In  commercial  tubes,  however,  the  material  is  not  strictly 
homogeneous  in  its  physical  properties  and  there  is  also  a slight 
variation  in  out-of-roundness  of  the  different  cross-sections,  from 
end  to  end,  as  well  as  a perceptible  variation  in  thickness  of  wall. 
Because  of  these  a commercial  tube  is  not  necessarily  weakest 
against  collapsing  pressure  at  the  middle  point  of  its  length,  as  is 
the  case  for  the  theoretically  perfect  tube. 

The  actual  relation  of  the  point  of  collapse  to  the  length  of 
tube,  for  the  several  hundred  commercial  tubes  tested,  is  shown  in 
Fig.  52.  This  chart  represents  a 20-foot  tube  divided  into  foot 
lengths  and  numbered  consecutively,  beginning  at  the  left-hand 
end.  Over  each  division  is  placed  the  Log  number  of  the  experi- 
mental tubes  that  collapsed  at  points  nearest  to  that  division. 


76  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


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Fig.  52. 


COLLAPSING  PEESSUEES  OF  LAP-WELDED  STEEL  TUBES.  77 

Thus,  experimental  tubes  Nos.  100,  433  and  505  collapsed  nearest 
the  9-foot  division  from  the  left-hand  end  of  tube,  while  Nos.  422 
and  452  collapsed  nearest  the  12-foot  division. 

It  will  be  observed  that  the  greater  number  of  the  tubes  collapsed 
at  points  that  are  at  distances  of  2 feet  and  18  feet  from  the 
left-hand  end,  that  is,  at  a distance  of  2 feet  from  either  end,  while 
comparatively  few  collapsed  at  or  near  the  middle  of  their  lengths. 
In  fact,  this  chart  shows  that  more  than  seven  times  as  many 
of  the  experimental  tubes  collapsed  at  two  feet  from  either  end 
than  at  a point  midway  between  the  ends. 

In  order  to  have  this  chart  show  the  relation  of  the  point  of 
collapse  to  the  nearest  end  of  the  tube,  it  is  obvious  that  we  should 
transfer  the  test  numbers  of  the  right-hand  half  to  the  correspond- 
ing columns  of  the  left-hand  half;  for  example,  we  should  trans- 
fer the  test  numbers  over  division  18,  which  is  two  feet  from  the 
right-hand  end,  to  the  column  over  division  2. 

This  has  been  done  for  all  the  columns  of  the  right-hand  half 
of  the  chart,  the  dashes  shown  being  made  to  represent  the  test 
numbers  of  the  right-hand  half  of  the  scale  transferred  to  the 
corresponding  columns  of  the  left-hand  half. 

Since  these  experimental  tubes  were  obtained  by  sending  in 
orders  in  the  usual  commercial  way,  presumably  they  were  taken 
at  random  from  the  company’s  stock,  and,  having  been  handled 
several  times  before  being  placed  in  the  test  cylinder,  it  is  ob- 
vious that,  since  it  is  not  known  in  which  direction  any  of  the  tubes 
were  passed  through  the  mill  while  being  manufactured,  no  sig- 
nificance can  be  attached  to  the  fact  that  a greater  number  of  the 
tubes  failed  nearer  the  left  than  the  right-hand  end.  This  chart, 
however,  shows  very  clearly  that  the  bulk  of  tubes  placed  under 
test  were  least  capable  of  resisting  fluid-collapsing  pressure  at  a 
point  near  one  end. 

The  reason  why  the  bulk  of  these  tubes  collapsed  near  one  end 
is  evidently  due  chiefly  to  the  following  two  facts,  namely,  (1) 
that  a tube  subjected  to  collapsing  pressure  is  weakest  at  the  point 
where  the  departure  from  roundness  is  greatest,  even  when  this 
is  small,  see  Tig.  54,  and  (2)  that  the  greatest  departure  from 
roundness  for  the  bulk  of  these  tubes  was  near  one  end,  see  Tig. 
53. 


78  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  53. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  79 


Chart  Showing  Relation  of  Greatest  Departure  from 
Roundness  to  Length  of  Tube. 

Fig.  53  shows  at  a glance  how  the  place  of  greatest  departure 
from  roundness  is  related  to  length  of  tube.  For  an  explanation 
of  the  manner  of  construction  see  the  description  of  Fig.  52,  the 
two  having  been  constructed  according  to  the  same  general  plan, 
the  only  difference  being  that  Fig.  52  shows  the  location  along 
the  length  of  the  tube  of  the  point  of  collapse,  while  Fig.  53  shows 
similarly  the  location  of  the  point  of  greatest  departure  from 
roundness. 

These  two  charts,  taken  in  connection  with  Fig.  54,  show  that 
the  element  of  greatest  weakness  in  a commercial  lap-welded  tube 
is  its  departure  from  roundness,  even  when  this  departure  from 
roundness  is  comparatively  small,  as  was  the  case  with  the  tubes 
tested.  Comparing  these  three  charts  with  Fig.  56,  it  will  be 
seen  that  the  thinnest  portion  of  wall,  while  in  itself  an  element 
of  weakness,  is  wholly  subordinate  to  out-of-roundness  in  its  in- 
fluence upon  the  collapsing  strength  of  commercial  lap-welded 
tubes. 

Relation  of  Axis  of  Collapse  to  Smallest  Diameter 

of  Tube. 

The  autographic  calipering  diagrams  taken  from  the  tubes  be- 
fore being  placed  in  the  hydraulic  test  apparatus  show,  as  was 
to  be  expected,  that  none  of  the  tubes  tested  were  exactly  round. 
This  departure  from  roundness,  while  measurable  by  the  refined 
methods  used  for  its  determination,  was,  nevertheless,  small,  vary- 
ing all  the  way  from  zero  to  as  much  as  possibly  2 per  cent,  of  the 
diameter.  It  is  apparent  that,  for  homogeneous  material  and  uni- 
form thickness  of  wall,  a tube  whose  cross-section  is  not  circular 
will  start  to  yield  in  the  direction  of  its  smallest  diameter,  and 
the  axis  of  collapse  will  be  coincident  with  the  original  smallest 
diameter  at  the  place  of  collapse. 

That  the  slight  out-of-roundness  of  the  tubes  tested  was  the  chief 
factor  in  determining  the  place  of  collapse  is  quite  apparent  from 
an  inspection  of  Fig.  54. 

This  chart  shows,  for  each  tube  whose  test  number  appears,  to 
the  nearest  5 degrees,  the  angular  distance  from  the  axis  of  col- 


80  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig.  54. 


CHART  SHOWING 

RELATION  OF  AXIS  OF  COLLAPSE 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


81 


* 


82  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


Fig. 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  83 


lapse  to  the  nearest  end  of  the  orginal  smallest  diameter  of  the 
cross-section  through  the  place  of  collapse.  Since  no  significance 
need  be  attached  to  the  plus  and  minus  signs  on  this  chart,  seeing 
that  had  any  tube  been  placed  in  a reversed  position  in  the  test 
apparatus  it  would  have  also  had  the  sign  of  its  angular  distance 
from  the  axis  of  collapse  reversed,  the  test  numbers  having  nega- 
tive angles  have  been  transferred  to  the  corresponding  columns  con- 
taining those  having  positive  angles.  In  order  to  avoid  confusion 
the  places  of  the  test  numbers  thus  transferred  are  indicated  by 
dashes. 


Relation  of  Axis  of  Collapse  to  the  Weld. 

Fig.  55  is  constructed  on  the  same  general  plan  as  Fig.  54, 
for  explanation  of  which  see  above. 

This  Chart  shows  that  the  angular  distance  from  the  weld  to 
the  axis  of  collapse,  for  the  different  test  numbers,  is  quite  uni- 
formly distributed  over  about  two-thirds  of  the  possible  distribu- 
tion and  shows  conclusively  that  the  weld,  in  itself,  is  not  an  ele- 
ment of  weakness  for  tubes  that  are  subjected  to  external  fluid 
pressure. 


Relation  of  Axis  of  Collapse  to  the  Thinnest  Portion 

of  Wall. 

Fig.  56  is  constructed  on  the  same  general  plan  as  Fig.  54, 
for  explanation  of  which  see  above. 

This  chart  shows  a fairly  uniform  distribution  of  the  test  num- 
bers over  about  three-fourths  of  the  possible  distribution  on  either 
side  of  the  axis  of  collapse,  with  a somewhat  prominent  increase 
over  the  remaining  fourth. 

A study  of  this  chart  in  connection  with  Fig.  54  will  lead 
to  the  conclusion  that  the  tendency  of  commercial  tubes  is  to  fail 
so  as  to  have  the  axis  of  collapse  at  right  angles  to  the  diameter 
through  the  thinnest  portion  of  the  tube.  It  should  be  observed 
in  this  connection  that  the  bending  action  on  the  wall  of  a tube 
while  being  collapsed  is  most  pronounced  at  this  same  point,  that 
is  to  say,  at  90  degrees  from  the  axis  of  collapse.  It  will  also 
appear,  from  these  same  charts,  that  for  commercial  lap-welded 
tubes  the  usual  departure  from  roundness  has  a more  pronounced 
effect  in  determining  the  manner  of  collapse.  In  other  words, 


84  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

when  these  two  influences  are  related  so  as  to  oppose  each  other 
the  latter  almost  invariably  predominates. 


Application  to  Practice  of  Stewart's  Formulae  A and  B 
for  the  Collapsing  Pressures  of  Lap-welded  Steel 

Tubes. 

Table  of  Collapsing  Pressures  and  Weights. — The  probable  col- 
lapsing pressures  contained  in  the  table,  Figs.  57  and  58,  were  cal- 
culated by  means  of  formulae  A and  B,  see  page  66. 

These  formulas  were  derived  from  results  of  tests  on  20 -foot 
lengths  of  Bessemer-steel  lap-welded  tubes.  They  are,  however, 
substantially  correct  for  any  length  greater  than  about  six  di- 
ameters of  tube  between  transverse  joints  or  end  connections  tend- 
ing to  hold  the  tube  to  a circular  form. 

In  the  columns  headed  “CLP.”  are  entered  the  probable  collaps- 
ing-fluid pressures  in  pounds  per  square  inch,  as  calculated  by 
formulae  A and  B;  while  in  columns  headed  “Wt.”  are  entered 
the  corresponding  plain-end  weights  in  pounds  per  foot  length. 
These  weights  were  calculated  on  the  basis  of  one  cubic  irch 
steel  weighing  0.2833  pound.  It  will  be  noted  that  each  weight 
column  and  the  corresponding  collapsing-pressure  column  taken 
together  constitute  a double  column  that  is  headed  by  the  outside 
diameter  of  the  tube  to  which  this  double  column  corresponds. 

Example  1.  Find  the  plain-end  weight  and  the  probable  collaps- 
ing pressure  of  a lap-welded  Bessemer-steel  tube  whose  outside 
diameter  is  6 inches  and  thickness  of  wall  0.180  inch. 

In  double  column  headed  “ 6 O.D.,”  Fig.  58,.  and  opposite  0.18 
in  the  extreme  left-hand  column  read  11.19  and  1214,  the  first 
being  the  required  plain-end  weight  in  pounds  per  foot  length  and 
the  second  the  probable  collapsing  fluid  pressure  in  pounds  per 
square  inch.  This  collapsing  pressure  is  for  a 20-foot  length 
between  transverse  joints  or  other  supports  tending  to  hold  the 
tube  to  a circular  form,  but  is  also  substantially  correct  for  any 
length  greater  than  about  6 diameters  or,  in  this  case,  3 feet. 

Example  2.  Find  the  collapsing  pressure  of  a tube  7 inches  out- 
side diameter  having  a plain-end  weight  of  17  pounds  per  foot. 

From  the  double  column  head  “ 7 O.D.,”  Fig.  58,  we  find  that 
a plain-end  weight  of  17.33  pounds  per  foot  corresponds  to  a 
probable  collapsing  pressure  of  1,586  pounds  per  square  inch,  and 
also  that  a weight  of  16.63  pounds  corresponds  to  a collapsing 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 


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86  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES, 


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Fig.  58. — Collapsing  Pressures  of  Steel  Tubes. — Continued. 


COLLAPSING  PRESSURES  OF  LAP-WEI.DED  STEEL  TUBES.  87 


R.Tj  Stewart  Williams  Eng.  Co.,  N.Y* 


Fig.  59. — Chart  showing  the  Values  of  the  Table  of  Collapsing  Pres- 
sures of  Lap-welded  Steel  Tubes,  Figs.  57  and  58,  Co  structed 
, to  a Vertical  Scale  of  Collapsing  Pressures  and  a Horizontal 
Scale  of  Thickness  of  Wall. 


88  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

pressure  of  1,462  pounds.  Now,  by  the  usual  method  for  interpo- 
lating it  will  he  found  that  for  a plain-end  weight  of  17  pounds  per 
foot  the  corresponding  collapsing  pressure  will  be  1,527  pounds  per 
square  inch. 

It  is  believed,  however,  that  the  tabular  values  in  this  table 
are  sufficiently  numerous  to  render  it  unnecessary  to  make  any 
interpolations  whatever  while  applying  it  to  practice. 

Factors  of  Safety . — It  must  be  remembered  that  these  tabular 
values  represent  the  probable  collapsing  pressures  as  based  upon 
the  tests.  This  being  the  case,  any  individual  tube  is  as  likely  to 
fail  above  as  below  this  most  probable  pressure.  The  relation  of 
the  collapsing  pressure  of  each  individual  tube  to  the  most  prob- 
able, as  tabulated,  is  clearly  shown  in  Figs.  48-50,  where  the 
curves  represent  the  tabular  values,  crosses  the  collapsing  pressures 
of  individual  tubes,  and  combined  crosses  and  circles  the  adjusted 
group  averages.  Expressed  in  per  cent.,  this  variation  of  each  in- 
dividual collapsing  pressure  from  the  tabular  is  shown  in  column 
9 of  Figs.  43-46.  This  table  shows  that  not  one  of  the  several  hun- 
dred tubes  tested  failed  at  a pressure  lower  than  42  per  cent,  of 
the  probable  collapsing  pressure,  while  \ of  one  per  cent,  of  the 
number  of  tubes  failed  at  37  per  cent,  and  2 per  cent,  at  25  per 
cent,  of  that  pressure.  In  other  words,  with  an  actual  factor  of 
safety  of  1.75,  as  based  upon  this  table,  Figs.  57  and  58,  not 
one  of  the  tubes  tested  would  have  failed. 

From  an  inspection  of  the  charts  and  table  above  referred  to 
it  would  appear  that : 

1.  For  the  most  favorable  practical  conditions,  namely,  when 
the  tube  is  subjected  only  to  stress  due  to  fluid  pressure  and  only 
the  most  trivial  loss  could  result  from  its  failure,  a factor  of  safety 
of  three  would  appear  sufficient. 

2.  When  only  a moderate  amount  of  loss  could  result  from 
failure  use  a factor  of  four. 

3.  When  considerable  damage  to  property  and  loss  of  life  might 
result  from  a failure  of  the  tube,  then  use  a factor  of  safety  of 
at  least  six. 

4.  When  the  conditions  of  service  are  such  as  to  cause  the  tube 
to  become  less  capable  of  resisting  collapsing  pressure,  such  as  the 
thinning  of  wall  due  to  corrosion,  the  weakening  of  the  material 
due  to  over-heating,  the  creating  of  internal  stress  in  the  wall  of 
the  tube  due  to  unequal  heating,  vibration,  etc.,  the  above  factors 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  89 


of  safety  should  be  increased  in  proportion  to  the  severity  of  these 
actions. 

Example  3.  By  means  of  the  table,  Big.  57,  find  what  thick- 
ness of  wall  a 4-inch  boiler  tube  should  have  in  order  to  withstand 
a working  pressure  of  200  pounds  per  square  inch,  with  a factor 
of  safety  of  eight. 

In  this  case  the  probable  collapsing  pressure  should  equal  the 
working  pressure  multiplied  by  the  factor  of  safety,  or  1,600 
pounds.  How,  looking  in  double  column  headed  “4  O.D.,”  we  find 
the  nearest  tabular  collapsing  pressure  to  be  1,647  pounds.  This 
corresponds  to  a thickness  of  0.14  inch  or  Ho.  9 B.W.G.,  as  read 
opposite  in  the  extreme  left-hand  column. 

Example  Bind  the  plain-end  weight  per  foot  of  a 6^-inch 
casing  to  withstand  a maximum  difference  between  external  and 
internal  fluid  pressures  corresponding  to  a water  head  of  800  feet, 
on  the  basis  of  a factor  of  safety  of  four. 

A table  of  hydrostatic  pressures  will  show  that  this  head  of 
800  feet  will  create  a fluid  pressure  of  347  pounds  per  square  inch, 
tending  to  collapse  the  tube  at  its  lower  end.  Multiplying  this 
by  the  factor  of  safety  we  get  1,388  pounds  per  square  inch  as  the 
probable  collapsing  pressure.  How,  looking  in  double  column 
headed  “6f,”  which  is  the  outside  diameter  of  a nominal  6^  casing, 
we  find  the  nearest  tabular  collapsing  pressure  to  be  1,361  pounds, 
which  corresponds  to  a plain-end  weight  of  14.39  pounds  and  a 
thickness  of  wall  of  0.21  inch. 

Chart  Showing  Relation  of  Collapsing  Pressure  to  . — Big. 

60  resulted  from  plotting  equations  A and  B (see  pp.  66-68)  to  a 
vertical  scale  of  probable  collapsing  pressures  and  a horizontal 
scale  representing  the  thickness  of  the  tube  divided  by  its  outside 

diameter,  or  the  ~ contained  in  these  formulae. 
a 

By  plotting  in  this  manner,  a single  line  may  be  made  to  repre- 
sent the  collapsing  pressures  of  a great  variety  of  tubes,  irrespect- 
ive of  their  individual  diameters  or  thicknesses  of  wall. 

It  will  be  noticed  that  this  is  the  same  curve  as  that  shown  in 
Big.  47,  the  difference  being  that  it  is  drawn  to  larger  and  more 
conveniently  read  scales. 

In  order  to  condense  the  size  of  this  chart  the  curve  is  broken 
into  the  two  parts  XX  and  YY.  By  this  means  the  area  of  the 
chart  has  been  reduced  to  about  one-fourth  of  that  which  would 


90  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

otherwise  have  been  required  to  construct  the  chart  to  the  scales 
shown.  It  will  be  observed  that  YY  is  the  upper  portion  of  XX 
transferred  to  the  left  and  then  dropped  down,  the  break  in  the 
curve  corresponding  to  a collapsing  pressure  of  2,080  pounds  and 
a thickness  divided  by  diameter  of  0.040.  It  will  also  be  observed 
that  the  scales  for  the  portion  XX  are  at  the  lower  and  right-hand 
margins,  while  those  for  the  portion  YY  are  at  the  upper  and  left- 
hand  margins. 

The  smallest  divisions  on  the  vertical  scale  represent  10  pounds 
collapsing  pressure,  while  those  on  the  horizontal  scale  represent 
0.0002  thickness  divided  by  outside  diameter.  When  reading  to 
the  nearest  smallest  division  on  these  scales  the  error  will  not  ex- 
ceed five  pounds  for  probable  collapsing  pressure,  nor  0.0001  for 
thickness  divided  by  outside  diameter. 

This,  then,  is  a universal  chart  showing  the  relation  of  the 
probable  collapsing  pressure  of  a tube  to  the  thickness  of  wall 
divided  by  outside  diameter.  It  represents  the  adjusted  values 
of  the  group  averages  of  all  the  20-foot  lengths  of  the  Bessemer 
steel  lap-welded  tubes  tested,  omitting  the  three  that  proved  to 
be  defective,  and  may  therefore  be  used  with  entire  confidence 
within  the  range  of  these  experiments ; that  is,  for  Bessemer  steel 
lap-welded  tubes  from  2 to  12  inches  outside  diameter,  and  for 
all  commercial  thickness  of  wall  in  lengths  greater  than  about  six 
diameters  of  tube  between  joints  or  end  connections  tending  to 
hold  them  to  a circular  form. 

Example  5.  Find  by  means  of  Fig.  60  the  probable  collaps- 
ing pressure  of  a tube  having  an  external  diameter  equal  to  6 
inches,  and  a thickness  of  wall  equal  to  0.203  inch. 

Dividing  the  thickness  of  wall  by  the  outside  diameter  we  get 

equal  0.0338.  Since  this  value  is  less  than  0.04  we  look  for 

it  on  the  scale  at  the  lower  margin  of  the  chart.  Having  found 
it  on  this  scale,  look  along  the  vertical  line  through  it  until  the 
line  XX  is  reached;  then  look  along  the  nearest  horizontal  line 
toward  the  right  and  read  from  the  scale  of  probable  collapsing 
pressures  1,540  pounds  per  square  inch.  This  is  the  probable  col- 
lapsing pressure  for  a length  of  20  feet,  but  is  also  substantially 
correct  for  any  length  greater  than  about  six  diameters,  or  3 feet 
for  a 6 -inch  tube,  between  transverse  joints  tending  to  hold  the 
tube  to  a circular  form. 

Linear  Units  for  d and  t. — It  should  be  noted  that  both  the  out- 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  91 


side  diameter,  d,  and  the  thickness  of  wall,  t,  must  be  expressed 
in  the  same  linear  unit  of  measure,  as,  for  example,  in  inches, 
centimeters,  millimeters,  etc.  The  name  of  the  linear  unit  is  im- 
material, the  chart  being  just  as  applicable  to  obtaining  probable 
collapsing  pressures  in  pounds  per  square  inch  when  the  diameter 
and  thickness  are  expressed  in  metric  as  when  in  English  units. 

Collapsing  Pressures  in  Metric  Measure. — First  divide  the 
thickness  of  wall,  t,  by  the  outside  diameter,  d , both  being  ex- 
pressed in  either  inches  or  millimeters.  Second,  obtain  from  Fig. 
60,  as  in  example  5,  the  probable  collapsing  pressure  in  pounds 
per  square  inch.  Third,  reduce  the  resulting  collapsing  pressure 
in  pounds  per  square  inch  to  that  expressed  in  kilograms  per 
square  centimeter  by  multiplying  by  the  conversion  factor  0.0703. 

Example  6.  Find  the  probable  collapsing  pressure  of  a tube 
whose  outside  diameter  and  thickness  of  wall  are  respectively  15 
centimeters  and  4 millimeters. 


Fifteen  centimeters  being  equal  to  150  millimeters,  g , or  thick- 


ness divided  by  outside  diameter,  equals  0.0266.  Proceeding  as 
in  example  5,  we  find  the  probable  collapsing  pressure  to  be  920 
pounds  per  square  inch.  Multiplying  this  by  the  conversion  factor 
for  reducing  English  to  metric  units,  given  above,  we  get  920 
multiplied  by  0.0703,  or  64.7  kilograms  per  square  centimeter. 

Example  7.  With  a factor  of  safety  of  eight  find  what  thickness 
a 3-inch  boiler  tube  should  have  in  order  to  resist  a working  exter- 
nal fluid  pressure  of  220  pounds  per  square  inch. 

In  accordance  with  these  assumptions  the  probable  collapsing 
pressure  of  the  tube  should  equal  the  working  pressure  multiplied 
by  the  factor  of  safety,  or  1,760  pounds  per  square  inch.  From 
Fig.  60  find  1,760  on  the  scale  of  probable  collapsing  pressures 
at  the  right-hand  margin,  and  look  along  the  horizontal  line  through 
this  point  until  line  XX  is  reached;  then  look  down  the  nearest 

vertical  line  and  read  0.0363  as  the  value  of  or  thickness  di- 


vided by  outside  diameter.  We  can  now  get  the  required  thick- 
ness of  wall  by  multiplying  the  value  of  ^ by  d , which  gives  us 

CL 


t equal  0.0363  X 3,  or  0.109  inch,  or  Xo.  12  B.W.G. 

For  the  same  conditions  of  pressure,  a tube  8 centimeters,  or 
80  millimeters,  diameter  should  have  a thickness  of  wall  equal 
0.0363  X 30,  or  2.9  millimeters. 


92  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

' . . . W 

Chart  Showing  Relation  of  Collapsing  Pressure  to  . — fig. 

61  resulted  from  plotting  equations  C and  D (see  page  68)  to  a 
vertical  scale  of  probable  collapsing  pressures  and  a horizontal 
scale  representing  the  plain-end  weight  per  foot  divided  by  the 

square  of  the  outside  diameter,  or  the  contained  in  the  for- 
mulae. The  errors  of  reading  this  chart  should  not  exceed  5 
pounds  for  the  probable  collapsing  pressure,  nor  0.001  for  the 
weight  divided  by  the  square  of  the  outside  diameter. 

This  chart  is  based  upon  precisely  the  same  experimental  data 
as  Fig.  60,  the  difference  being  that  for  any  given  size  of  tube 
this  chart  shows  the  relation  of  the  probable  collapsing  pressure 
to  the  plain-end  weight,  while  the  preceding  chart  shows  its  rela- 
tion to  the  thickness  of  wall.  This  chart  should  be  used  in  cal- 
culations relating  to  collapsing  pressure  when  the  plain-end  weight 
is  either  given  or  required,  while  the  preceding  chart  should  be 
used  when  the  thickness  of  wall  is  given  or  required. 

Example  8.  Find  the  probable  collapsing  pressure  of  a 6f 
(7  0.  D.)  inch  casing  whose  plain-end  weight  is  17  pounds  per 
foot. 

Dividing  the  plain-end  weight  in  pounds  per  foot  by  the  square 
of  the  outside  diameter  in  inches  we  get  equal  0.347.  Find- 
ing this  value  on  the  scale  at  the  lower  margin  of  Fig.  61  we 
look  vertically  until  the  line  XX  is  reached,  then  look  horizontally 
toward  the  right  and  read  1,525  pounds  per  square  inch  as  the 
probable  collapsing  pressure  required. 

While  this  value  is  for  a 20-foot  length  of  tube,  as  in  the  pre- 
ceding chart,  it  may  be  used  without  substantial  error  for  any  , 
length  greater  than  about  six  diameters,  or  in  this  case  3^  feet, 
between  joints  tending  to  hold  the  tube  to  a circular  form. 

Example  9.  Find  the  plain-end  weight  per  foot  of  a 5f-inch 
casing  (6-inch  O.  D.)  to  withstand  a maximum  difference  between 
external  and  internal-fluid  pressures  corresponding  to  a water  head 
of  1,200  feet,  on  the  basis  of  a factor  of  safety  of  four. 

A table  of  hydrostatic  pressures  will  show  that  this  head  of 
1,200  feet  will  create  a fluid  pressure  of  520  pounds  per  square 
inch,  tending  to  collapse  the  casing  at  its  lower  end.  Multiply- 
ing this  by  the  factor  of  safety  we  get  2,080  pounds  per  square 
inch  as  the  probable  collapsing  pressure.  Finding  this  value  on 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  93 

the  left-hand  margin  of  Fig.  61,  we  look  horizontally  toward 
the  right  until  line  YY  is  reached,  then  up  the  nearest  vertical 

line  and  read  0.41  as  the  value  of-^-  > or  plain-eud  weight  di- 
vided by  the  square  of  the  outside  diameter.  Now  since 

equals  0.41,  w will  equal  0.41  multiplied  by  the  square  of  the 
outside  diameter,  or  0.41  X 36  = 14.76  pounds  per  foot,  as  the 
required  plain-end  weight. 


DISCUSSION. 

Mr.  Henning. — I wish  to  compliment  the  author  for  the  char- 
acter of  the  paper  that  he  has  presented  as,  in  my  opinion,  it 
contains  valuable  information  which  the  Society  was  not  in 
possession  of  before.  Of  course,  a great  deal  of  time  has  been 
spent  on  it,  and  somebody  has  spent  a lot  of  money  on  it,  but  it 
gives  us  information  which  is  valuable. 

I wish  that  manufacturers  generally  would  give  us  as  much 
information  about  what  they  produce  as  has  been  given  here,  so 
that  we  may  know  what  material  will  do  after  it  is  finished,  and 
not  alone  what  it  will  do  when  it  is  in  the  shape  of  a test  piece. 

Mr.  William  T.  Donnelly. — I would  like  to  ask  whether  the 
tube  was  tested  while  in  the  horizontal  position  or  whether  it 
was  placed  in  a vertical  position  for  testing? 

Professor  Stewart. — These  tubes  were  all  tested  in  a horizontal 
position.  An  investigation  was  made  as  to  what  effect  the  position 
would  have  upon  the  collapsing  strength  of  the  tubes,  and  I satis- 
fied myself  that  it  had  no  noticeable  effect.  Many  of  the  tubes 
were  of  such  weight  as  to  tend  to  float  up,  and  they  would  have 
floated  to  the  top  of  the  test  cylinder  had  they  been  permitted 
to  do  so.  This  was  due  to  the  fact  that  while  under  test  the 
tubes  were  open  to  the  atmosphere  on  the  inside,  and  were  sur- 
rounded by  water  on  the  outside.  Others,  of  course,  tended  to 
sink.  In  either  case  the  resulting  strain  was  quite  insignificant. 

Mr.  Rice. — As  Chairman  of  the  Committee  on  Papers,  I desire 
to  express  my  personal  appreciation  to  the  author  of  this  paper. 
As  far  as  I remember,  it  is  the  most  remarkable  paper  presented 
at  any  meeting,  and  it  represents  an  indescribable  amount  of 
work,  and  I think  we  should  take  special  notice  of  it  on  that 
account.  Then  it  is  notable  in  respect  of  the  contribution  it 


94  COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES. 

makes  to  the  knowledge  that  we  have  on  the  subject.  I consider 
that  one  of  the  special  functions  of  the  Society,  to  contribute  to 
human  knowledge. 

In  this  connection  I want  to  bring  out  that  many  of  our 
members  may  have  knowledge  of  valuable  data  or  information 
which,  if  the  request  be  properly  made  to  the  gentlemen  who  control 
it,  will  be  permitted  to  be  published  for  the  benefit  of  the  pro- 
fession. 

A Guest. — Some  time  ago  I had  occasion  to  go  before  the 
Board  of  Supervising  Inspectors  on  a subject  which  is  covered  very 
largely  by  this  paper.  The  occasion  for  it  was  that  the 
Board  of  Supervising  Inspectors,  at  one  of  their  meetings,  in 
their  wisdom,  had  made  a new  rule  designating  the  thickness  of 
flues  in  steam  boilers  coming  under  the  regulations  of  the  marine 
service,  upon  a formula  which  took  no  cognizance  of  the  length 
of  flue.  It  was  not  Clark’s  formula,  hut  I think  some  formula 
that  had  been  adopted  by  the  British  Lloyds  before  the  Fairbairn 
experiments  had  been  measured  up.  For  a year,  under  the  hasty 
action  of  the  Board  of  Supervising  Inspectors,  the  condition  of 
the  work  done  for  marine  practice  was  quite  chaotic,  but  was 
finally  relieved  to  some  extent  by  the  Secretary  of  the  Treasury 
suspending  the  rule.  How  I hope  that  this  paper  will  come 
to  the  knowledge  of  the  U.  S.  Board  of  Supervising  Inspectors, 
because  they  need  it.  They  need  it  now  almost  as  badly  as  they 
did  at  the  time  I speak  of.  Through  the  efforts  of  some  person, 
whose  interests  were  more  largely  concerned  perhaps  than  the 
members  of  the  Board  of  Supervising  Inspectors,  a formula  was 
adopted  which  did  take  cognizance  of  the  length  of  flue.  How, 
I would  like  to  ask  for  my  own  information  from  Professor 
Stewart,  whether  he  knows  from  his  experiments  how  they  com- 
pare with  the  existing  formula  of  the  Board  of  Supervising  In- 
spectors. 

How  as  to  the  matter  of  the  failure  of  the  tubes.  The  experi- 
ments would  seem  to  indicate  that  the  tubes  which  were  tested  have 
perhaps  in  rolling  been  laid  on  a stand,  which  tended  to  flatten 
the  tubes  at  the  particular  points  where  they  were  laid  down. 

Professor  Stewart. — I have  not  made  as  yet  any  such  compari- 
son as  has  been  spoken  of ; but  I am  satisfied,  however,  that  plain 
commercial  tubes  in  lengths  of  about  six  diameters  are  no  stronger, 
to  anysg>rpj^feftb¥x^t^peast,  than  similar  tubes  having  lengths 
up  to  say  zO  feet  or  more.  This  is  clearly  brought  out  in  the 

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Transactions  American  Society  op  Mechanical  Engineers,  Vol.  27. 


Reid  T.  Stewart. 


I SHOWING  THE  INFLUENCE  OF  LENGTH  OF  TUBE  ON  THE  COLLAPSING  PRESSURE, 
SERIES  1 < for  lengths  of  zi  to  20  feet,  between  end  connections  tending  to  hold  the  tube  too  circular 

( form.  For  on  outside  diameter  of  Ox  inches  and  thicknesses  from  0.130  to  0.322  inches. 


PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 
NATIONAL  TUBE  CO’S  LAP-WELDED  BESSEMER  STEEL  TUBES 

CONDUCTED  BY  PROF.  RT  STEWART,  1902-4  F PK ,1905 


Test 

Number 

Outside  Diameter 

Thickness 

o f Wall 

Length  of  Tube 

Weight  at  Tube 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis  % 

Material 

Remarks 

Commercial  Designation  of 

Tube  as  Reported 

Nominal 

Average 

At  Place  of 
Collapse 

nominal 

Average 

As 

, 

Pounds 

Sg  Inch 

Used 

Length 

End 

Distance 

tbtrens,h/ 

Sgllru  'Inch 

Etanfohen 

%>n^S 

of  Are* 

S.hcon 

Pho  3 

Mang 

Carbon 

Or..:,! 

L.o„ 

Lease 

Nominal 

Actual 

In  Feet 

m a, a; 

, 

2 157 





cm 

0.190 

o no 

20  120 

19  9/8 

15.92 

4 SO 

_ 

*'  o - 

9 3 

,, 

O' 

- 12“ 

5g  410 

35  670 

26/3 

57  tO 

005 

.069 

109 

35 

08 





2 

9 63  7 

o./ts 

0./79 

19  992 

1?  696 

17  24 

625 

6'  3m 

2 7 

IS 

6' 

- 30“ 

60  490 

39  030 

21.04 

57.20 

006 

/It 

.3  2 

.075 

3 

t 625 

t 64/ 

0 180 

0 / 84 

0.162 

20'  0* 

/9  997 

19  695 

16.07 

16.77 

535 

B 

5'  6‘ 

4 

3 * 

60  020 

36  420 

24  00 

58  73 

.006 

II  5 

.3  1 

.0  75 

Bessemer 

fi  Casmg  10  07/0* 

4 

9 440 

— 

— 

0 IS3 

0/9/ 

0 171 

20.004 

19  702 

16.54 

450 

— 

S’  6' 

7.7 

15 

3" 

- 30“ 

59  640 

35  S 10 

2/92 

59  43 

006 

.079 

3 2 

02 

— 

Steel 

— 

5 

9 631 

— 

— 

0.191 

0 197 

0 173 

20.0/1 

19  709 

17.23 

620 

— 

5 ' O' 

7.0 

4 

?' 

+ 15“ 

5 ? 160 

36  350 

23.00 

5 7 50 

.010 

.067 

.106 

3 / 

0 75 

— 

— 

firerogt 

t 643 

0 125 

0.171 

o nz 

2a.au 

19.724 

U.74 

536 

S’  t 

7.7 

5?  344 

3*  396 

23.22 

5 2.  S3 

007 

074 

3 2 

.07  7 

4 

t 65/ 

— 

— 

0 196 

0 .192 

o 184 

/ 5.0/0 

14.708 

/ 6.92 

S75 

— 

6‘  0 " 

2.3 

4 

O' 

- t' 

52  100 

37  060 

If  54 

52  60 

.015 

.072 

.108 

3 5 

075 





7 

t 65/ 

— 

— 

0 174 

0./7S 

0.145 

15.025 

14.723 

15.76 

425 

— 

*'  0" 

8.3 

9 

O' 

- 27“ 

56  410 

35  610 

20  75 

5 6 90 

.008 

.06  5 

1 C 5 

3 3 

■ 08 

— 

— 

f 

9.525 

f 6 55 

0/80 

0.193 

0./94 

0.162 

/s'o“ 

15.004 

14.702 

16.07 

16.545 

55  0 

B 

8.3 

- 25“ 

SS500 

36  600 

2/46 

57.40 

.015 

073 

.103 

.3  3 

.075 

Bessemer 

ti  Casing  16  07  lbs 

9 

g *55 

— 

— 

0.191 

0.2/5 

0.1  82 

15.010 

14.709 

17.21 

6/0 

— 

6’  O' 

2.3 

4 

o' 

-173“ 

52  520 

37  890 

2/ .79 

5 6.70 

.008 

■ 073 

.112 

3 3 

.07 

— 

Steel 

— 

1 0 

g 652 

1 

— 

0.199 

0.191 

0.192 

15.002 

14.700 

16.95 

5 90 

— 

6'  6" 

9.0 

7 

6' 

4 14“ 

59  950 

36  S 50 

23  21 

55  30 

.006 

.071 

34 

.0  75 

— 

— 

Ruermg* 

2.453 

0 194 

0 195 

0.172 

15.0/0 

!4  708 

16.66 

5 49 

*'  r 

2 4 

57  496 

36  742 

21  15 

56.98 

.010 

.071 

.106 

34 

075 

, / 

g 662 

— 

— 

0 194 

0.222 

0 192 

10.017 

9 7/5 

16  65 

575 

— 

s’  o " 

7.0 

3 

f 

4 27“ 

57  590 

35  340 

22.52 

60.50 

.008 

.068 

.in 

3 5 

.02 





/ 2 

g 654 

— 

— 

0 180 

0.190 

0./74 

9.993 

9 69/ 

16  26 

570 

— 

5'  O' 

7.0 

3 

/' 

4135“ 

59  410 

38  5 20 

23.75 

60.30 

.010 

.076 

.110 

3 / 

.075 

— 

— 

t 62  5 

0 180 

0 177 

0 197 

0.17  3 

/o'  o' 

9 997 

9 675 

16.07 

/ 6.03 

59  0 

B 

5'  6" 

7.7 

3 

55  990 

34  200 

24.59 

60.47 

.065 

.2  3 

.02 

Bessemer 

/ 4 

9 649 

— 

— 

0 17/ 

0 .190 

0./55 

9.797 

9.695 

15.5/ 

455 

— 

* 9 ' 0" 

*/  2.5 

5 

9' 

4 67“ 

60  220 

37400 

21  67 

51.20 

— 

.07? 

110 

3 8 

.02  5 

— 

Steel 

R 

• 5 

8 65/ 

— 

| 

0 178 

0 197 

0.173 

!0. 007 

9.7  OS 

I6.H 

550 

— 

S’  6 • 

77 

5 

3' 

4 90“ 

59  490 

38  430 

21  98 

57.10 

.006 

.069 

.113 

.3  5 

.07  5 

— 

— 

4tere,e 

8 656 

0 178 

O./ff 

0.171 

1 0.002 

7 700 

16.1  1 

542 

S’  J" 

7.4 

St  SI9 

36  77 8 

2/  8? 

57.91 

009 

.071 

.112 

32 

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/ 6 

2.650 

— 

— 

0 182 

0 196 

0/52 

4 990 

4 688 

16  43 

6 / 5 

— 

5'  O' 

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2 

*- 

4 32“ 

— 

— 

— 

— 

— 

.070 

106 

3 2 

07 





t 7 

9 65? 

— 

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0 .197 

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5.0/0 

4 708 

16  42 

575 

— 

5 ' 0' 

7.0 

2 

7“ 

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— 

— 

— 

— 

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062 

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— 

— 

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0.180 

0 180 

0 ISS 

5 O' 

4.702 

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1 6.34 

5 40 

B 

5'  0" 

2 

8" 

4/07 * 

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II  7 

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8.645 

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0.173 

— 

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5.020 

4.7/9 

15.64 

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7.0 

2 

6' 

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— 

— 

— 

— 

— 

0 9 f 

113 

3 7 

02 

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— 

— 

0 122 

0./90 

0 179 

5.005 

4.703 

16  43 

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2 

3' 

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— 

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— 

— 

— 

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0 190 

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4.704 

16  25 

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073 

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2 500 

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0.189 

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2.5/5 

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2/5 

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0.185 

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3.5 

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32 

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24 

8.655 

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0 140 

2.5/4 

2.2/2 

154/ 

1095 

c 

— 

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3.5 

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3' 

0“ 

— 

— 



— 

— 

100 

118 

■ 3 6 

.08 

— 

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g 64/ 

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2.507 

2.205 

1643 

99S 

C 

— 

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3.5 

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3“ 

1 4iii“ 

— 

— 

— 

— 

— 

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112 

3 2 

07 

— 

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9 656 

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0 18  5 

0 163 

2 5 12 

2 2/0 

15  99 

977 

2'  *' 

3.5 

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114 

32 

075 

2 C 

8 604 

g St 

0 219 

0 230 

0.2/0 

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19/69 

18  866 

/9  57 

8 70 

e 



s‘  *• 

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!4 

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5 6 700 

34  060 

22.7? 

57  40 

006 

068 

105 

3 8 

.07 



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2 7 

9 622 

g 44 

0 233 

0 239 

0.186 

/ 3'  8' 

13  675 

13.373 

20.75 

II /S 

c 

— 

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to 

/ - 

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57  770 

34  730 

22  33 

53  70 

— 

070 

102 

3 2 

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g *25 

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2 63 

0 22? 

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12  932 

12  630 

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19  23 

9 S 0 

B 

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2 

2“ 

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60  530 

37  700 

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57  20 

— 

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117 

3 5 

02 

— 

Bessemer 

— 

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29 

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t 69 

g 62 

0 213 

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72  674 

12.372 

19  16 

7 50 

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f 

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Fig.  11.— Tabular  Statement  op  Principal  Results  op  Tests,  Series  1. 


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Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 


Reid  T.  Stewart. 


r SHOWING  THE  INFLUENCE  OF  LENGTH  OF  TUBE  ON  THE  COLLAPSING  PRESSURE.  J<#  „mMrkt  kn  akkkrk,  s/,.„  PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 

SERIES  1 l for  lengths  of  2t  to  20  feet,  between  end  connections  tending  to  hold  the  tube  to  a circular  N- N.t  eoZred”"  NATIONAL  TUBE  CO’S.  LAP-WELDED  BESSEMER  STEEL  TUBES 

( form.  For  an  outside  diameter  of  Oi  inches  and  thicknesses  from  O.IBO  to  0 322  inches.  CONDUCTED  BY  PROP.  R.T.  STEWART,  1902-4.  F.P.K.J905. 


Test 

Number 

Outside  Diameter 

Thickness 

»f  Wall 

Length  of  Tube 

* Feet 

Weight  of  Tube 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemico  / 

lno/ysis  % 

Material 

Remarhi 

Commercial  Designation  of 

Tube  os  Reported. 

Nominal 

Average 

McZ,napxtf 

Nominal 

Average 

A*  Pla 
Coll 

cm  of 
pse 

/fa 

Sf.  Inch 

Gege 

Amta  of 

Length 

End 

Angular 
Distance 
from  Weld 

Strength 
llt.parSf  In 

Yield  Point 
Peunde  per^ 

Hah  fatten 

fteieethm 

of  Area 

7- 

5.  >w 

PAS 

Hang 

darken 

Oxide 

Graatasf 

toast 

Croatia*  t 

least 

Reported 

Nominal 

//dual 

lUpeaSt*. 

In  Feet 

In  Oie's. 

6 0 

9 673 

8.685 

8.640 

0.276 

0.290 

0.265 

7 750 

7.576 

24.75 

1850 

44 

y 

0 " 

7 0 

y 

y 

t-  5* 

58  510 

36  730 

23.42 

53.20 

.075 

/( 

.41 

.08 



6 / 

8.668 

t 685 

9.62  5 

0.265 

0.290 

0.256 

10.0/0 

7.656 

23.75 

1150 

1.6 

2‘ 

10 “ 

3.7 

9' 

- ,4t * 

S8  980 

37  980 

23.34 

54.60 

.075 

.36 

.07 

62 

9 625 

8 677 

8.685 

8.655 

0271 

0.281 

0.261 

10'  0" 

9.970 

7 636 

24.38 

24.05 

1628 

c 

2.7 

4‘ 

6 " 

63 

2' 

52  800 

35  220 

! 3.9/ 

34  50 

35 

08 

Bessemer 

Oi' Casing  2430  Lbs 

6 3 

8.662 

8 675 

8.660 

0.26  7 

0.29  5 

0.259 

7.795 

7 64/ 

23.74 

158  5 

3.7 

T 

0 

77 

S' 

0 " 

0 • 

58  720 

37  7 50 

22.30 

SI  10 

— 

.080 

.1) 

J7 

.075 

— 

Steal 

— 

64 

8.657 

8.675 

2.6/5 

0.260 

0.283 

0.234 

10.020 

7.666 

23.28 

1450 

1 7 

5 ' 

6 0 

7.7 

S' 

6" 

-no9 

56  67 0 

34  130 

26.96 

61  50 

— 

.065 

.li 

.42 

.0  75 

— 

— 

fiveragp 

t.661 

8.681 

8.637 

0.267 

0.288 

0.255 

9.773 

7 639 

23.75 

1533 

2.7 

5' 

0 " 

6 9 

57  136 

36  362 

2/  99 

5 0.98 

082 

n 

.38 

.076 

65 

8.656 

8.665 

8 635 

0.277 

0.325 

0.260 

4 980 

4 626 

24.80 

1750 

3.7 

S' 

0 - 

7.0 

2' 

7" 

4 10 * 











.064 

19 

.37 

.075 

— 

— 

6 6 

8.653 

8.675 

8.645 

0.262 

0.280 

0.260 

4.995 

4.641 

23.97 

1520 

A 7 

s' 

7.0 

3' 

4 so * 

.089 

.41 

.08 

67 

8.625 

8.6  SI 

8.665 

2.615 

0.271 

0.269 

0.300 

0.250 

S'  0 " 

4.995 

4 641 

24.38 

24.07 

1640 

c 

5.2 

5‘ 

7.0 

2 ' 

7" 

4100 * 

.083 

.35 

.075 

Bessemer 

8*' Casing  24  38  Lbs. 

68 

8.648 

8.655 

8.615 

0.257 

0.277 

0.233 

4.992 

4.638 

22.77 

1345 

6 

5' 

0" 

7.0 

2' 

7“ 

- 35* 

— 

— 

— 

— 

— 

.077 

./2 

.37 

.075 

— 

Steel 

— 

6 7 

8.670 

8 675 

2.665 

0.26  8 

0.274 

0.255 

5.005 

4.651 

24.02 

1725 

4 2 

5' 

o' 

7.0 

2' 

6 * 

-135* 

— 

— 

— 

— 

— 

.122 

13 

.30 

.07 

— 

— 

8.656 

8.671 

8.635 

0.268 

0.277 

0.252 

4 793 

4.637 

23.77 

1636 

3.7 

5' 

o - 

7 0 

087 

/» 

.36 

.075 

7 0 

8 673 

8 670 

8.625 

0.253 

0.266 

0 221 

2.501 

2.147 

22.72 

1475 

3.0 

2 • 

y 

3 5 

O' 

,y 

-120- 











.077 

.10 

.35 

07 



R 

7 / 

8.650 

8.655 

8.625 

0 27/ 

0.307 

0.267 

2.500 

2.146 

24.20 

1730 

4 3 

2 ‘ 

3.5 

- ,5* 

.082 

.41 

.08 

7 2 

8.625 

8.662 

8.665 

8.645 

0.271 

0.273 

0.317 

0.258 

2'  6" 

2.480 

2.026 

24.39 

24.47 

1880 

c 

2.7 

2‘ 

3.5 

2 • 

079 

.27 

.075 

Bessemer 

si'c.t.no  east  10  3. 

73 

8.680 

8.675 

9 630 

0.267 

0.312 

0.252 

2.470 

2.136 

24.15 

1850 

4.8 

2‘ 

y 

3.5 

, • 

2" 

4 / 3 * 

— 

— 

— 

— 

— 

.077 

■ 1 1 

.36 

.075 

— 

Steel 

A 

7 4 

8 644 

8.620 

9.620 

0.274 

0.273 

0.250 

2.500 

2.146 

24.50 

1785 

2.6 

2' 

6” 

35 

1 ' 

3" 

- 15* 

— 

— 

— 

— 

— 

.094 

.10 

.31 

.07 

— 

R 

Average 

8.662 

8.665 

8.629 

0.268 

0.27S 

0.250 

2.474 

2.120 

24.01 

1784 

3.5 

2 " 

6" 

3.5 

082 

JO 

.34 

.074 

7 5 

8.640 

8.675 

8.605 

0.274 

0.282 

0.260 

20‘  0" 

20.003 

17.647 

24.44 

1375 

4 1 

y 

i 

8.7 

14' 

2 ' 

4 6 8* 

55  680 

32  880 

24.54 

6/00 

010 

.061 

ID 

.35 

.08 

— 

Bess  Steel 

R 

7 6 

8.663 

8.685 

8.655 

0.272 

0.272 

0.271 

20'  0“ 

17.788 

17. 634 

24.38 

1410 

3.4 

— 

14' 

II" 

4 40* 

59  290 

35  5 30 

1 8.63 

58.00 

— 

.065 

id 

.40 

.09 

— 

— 

77 

8.625 

8.660 

8.66S 

8.605 

0.281 

0.274 

0.3/1 

0.262 

I9'I0“ 

19.855 

19.501 

25.00 

24.47 

1275 

c 

7 J 

7' 

7“ 

10.9 

7 

5’ 

- 120 * 

43  7 40 

25  240 

15.21 

28.30 

— 

.017 

.14/ 

Tract 

Traca 

1.68 

West  Iren 

A 

8' Line  Pipe  25.00  Us 

7 8 

8.660 

8.700 

2.575 

0.280 

0.294 

0.274 

18'  7’ 

/8  750 

18.376 

25.08 

1250 

7.5 

7' 

0" 

7.7 

7' 

3' 

4 92* 

45  5 10 

29  520 

13.21 

25.30 

0 54 

.038 

.1 10 

.1  1 

.06  5 

2.58 

A 

77 

8.664 

8.670 

8.650 

0.266 

0.280 

0.246 

19'  4" 

IS. 340 

17  78  6 

23.84 

1425 

8.5 

6' 

6" 

7.0 

IS' 

3' 

-135* 

46  430 

26  710 

15.92 

26  80 

062 

.040 

.119 

.11 

.065 

1.72 

A,N 

to 

8.656 

8.675 

8.585 

0.266 

0.301 

0.258 

15.000 

14.646 

23.85 

1385 

2.7 

f 

6* 

70 

10' 

4 - 

-100* 

56  310 

34  860 

23.67 

59.50 

006 

.064 

.106 

.33 

075 

— 

— 

t l 

8.666 

8.735 

8.575 

0.276 

0.286 

0.270 

14.775 

14.641 

24.73 

1305 

3.8 

2". 

0* 

58  500 

34  5 90 

23.50 

61.20 



.061 

.no 

41 

.08 

82 

8 625 

8 662 

8.705 

8.625 

0.281 

0.271 

0.276 

0.256 

/S'  0 " 

14.770 

14.636 

25.00 

24.27 

1470 

c 

4.5 

y 

3" 

9 7 

4 ' 

8" 

0* 

58  6/0 

38  720 

21.42 

57  80 

— 

.057 

.105 

.35 

.08 

— 

Bessemer 

R,N 

8 line  Pipe  26-oe  Lbs 

123 

8.665 

8.675 

8.650 

0.277 

0.305 

0.287 

14.775 

14.64/ 

26.47 

1675 

y 

6" 

90 

4' 

2“ 

4 35* 

58  130 

34  560 

20.84 

58.90 

— 

.090 

.105 

31 

.07 

— 

Steel 

— 

124 

8.644 

8.675 

8.5  75 

0.263 

0.277 

0.253 

14.775 

14.641 

23.5  6 

1250 

3.5 

6‘ 

J' 

87 

3' 

9 ' 

4 ,5* 

59  710 

35  300 

23.76 

56  10 

.005 

007 

.121 

34 

07 

— 

Average. 

8.657 

8.705 

8.606 

I.Z75 

0.287 

0.265 

14.775 

14.641 

24.58 

,42 1 

4.0 

b ' 

S" 

87 

5 8 252 

35  646 

22  68 

58  70 

.072 

109 

35 

075 

8 3 

8.667 

8.725 

8.595 

0.270 

0.305 

0.263 

10.0/2 

7.659 

24.20 

1440 

3 5 

y 

0" 

8.4 

7 

2“ 

4 8* 

58  510  j 

34  710 

24  79 

58  20 



058 

no 

.38 

.08 

— 

— 

8 4 

8.675 

8 710 

2.670 

0.275 

0.27 1 

0.247 

10.002 

7.648 

24.72 

not 

y 

b" 

7.0 

5 

4- 

4/52 ' 

57  250 

36  270 

19  6 7 

5 8 90 



.065 

.103 

.30 

.065 

— 

A.N 

8 5 

8.625 

8.664 

8.68  5 

8.615 

0.28 1 

0.260 

0.273 

0 240 

/O'  0" 

10.000 

7.646 

25.00 

23  28 

1575 

c 

4.7 

6' 

3" 

8.7 

4- 

S * 

58  240 

36  400 

23.00 

59  60 

— 

.070 

.112 

.31 

.08 

— 

Bessemer 

— 

8 "Line  Pipe  2500  Lbs. 

8 6 

8 663 

8.675 

8 565 

0.278 

0.286 

0.260 

7.790 

7.636 

24.85 

1 545 

4.8 

b ■ 

3“ 

8.7 

b 

2‘ 

—132* 

57  340 

35  720 

21  00 

58.40 

__ 

.070 

109 

.34 

.08 

- 

Sre*l 

8 7 

8 664 

8.670 

8.615 

0.272 

0.284 

0.268 

10.010 

7.656 

24.40 

1645 

4.1 

6' 

y 

8.7 

4 

10" 

4/65* 

58  770 

33  910 

24  58 

58.00 

— 

.071 

123 

.36 

075 

— 

— 

Antra  fa 

8.671 

8.677 

8.6 10 

0.271 

0.272 

0.256 

10.003 

9.647 

24.27 

1541 

4.7 

S'  3 * 

8.7 

58  422 

35  402 

22.61 

58  62 

067 

in 

.34 

.076 

• 

2 

J 

4 

5 

6 

7 

8 

9 

10 

II 

12 

13 

U 

,7 

!$ 

If 

20 

21 

22 

23 

24 

2 5 

26 

27 

28 

27 

30 

■*' 

32 

33 

J4 

Fig.  13.— Tabular  Statement  of  Principal  Results  of  Tests,  Series  1 


. 


■V.YZ^.xVV  1V\  r.v.  - vv>-?  .V\  <-'V\ 

& , \n  1W  Mmji  .an«4>  Tii\»  c\ ■..■hu'j<.  .Vv&YV;  .'•  <\  >•-.  v .V^.  1 

T iV  ' <t  A*»St  • j’Y 


Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 


Reid  T.  Stewart. 


Fig.  14.— Tabular  Statement  of  Principal  Results  of  Tests,  Series  1. 


Transactions  American  Society  op  Mechanical  Engineers,  Vol.  27. 

SHOWING  THE  INFLUENCE  OF  LENGTH  OF  TUBE  ON  THE  COLLAPSING  PRESSURE . 

SERIES  1 { for  lengths  of  22  to  20  feat . between  end  connections  tending  to  hold  the  tube  to  a ci rev  for 

form  For  an  outside  diameter  of  Si  inches  and  thicknesses  from  0180  to  0.322.  inches. 


Reid  T.  Stewart. 

PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 
NATIONAL  TUBE  CO'S.  LAP-WELOEO  BESSEMER  STEEL  TUBES 
coNQocreo  by  prof  r r.  stewart,  / 902-4  f.p.k.hos. 


Test 

Number 

Outside  Diameter 

Inches 

Thickness 

i of  Wall 
hes 

Length  of  Tube 
* Feet 

Weight 

Lbs.pt 

of  Tube 

tr  Foe/. 

Collapsing  Pressure 

Collapsed  Por  tion 

Physical  Properties 

Chemiea/  Analysis  % 

Materiel 

Remark  s 

Commercial  Designation  of 

Tube  as  Reported 

T 

Average 

hr  Place  Of 
CoRapme 

Nominal 

Average 

hr  Piece  ef 
Collapse 

hs 

Reported 

Refuel 

Sg.  Inch 

Gage 

L ength 

Oi St  a nee 

End 

Distance 

Strength 
Lbt  perSg  In 

Yield  Point 
Pounds  per 
Square  Inch 

ftongeth* 

Ot'chfs 

hedochon 

of  Rroa 
% 

Silicon 

Sulphur 

Phot. 

Co  r ben 

Onde 

Create  st 

Least 

Greatest 

Least 

Rommel 

Refuel 

L**f»S~ 

In  Feet 

in  Bio’s. 

113 

2 645 

t 670 

8.625 

0.294 

0.309 

0.266 

2 512 

2.158 

26.22 

2450 

2.6 

2'  6" 

35 

no’ 

- 140 * 











.093 

112 

27 

065 



119 

2 641 

2 650 

2 600 

0.322 

0.360 

0.314 

2 500 

2 146 

22.60 

2490 

2 6" 

3.5 

4 20’ 

.070 

107 

36 

075 

A 

120 

9 625 

9 640 

2 650 

2 615 

0.323 

0 35 5 

0 31 1 

2 ' 6' 

2.505 

23  570 

28.177 

29  64 

2390 

C 

2'  6" 

3 5 

/ ' 6“ 

-123’ 

.063 

.102 

33 

.0  7 

Bessemer 

8‘  tme  Pipe  28  1 77  Us 

121 

8 657 

2.660 

2 640 

0.319 

0.305 

0.276 

2.520 

2.170 

22.43 

2290 

7 0 

2'  6 * 

3.5 

/ J" 

0 • 

— 

— 

— 

— 

— 

.090 

115 

.35 

075 

— 

A 

122 

2 645 

8 660 

8.615 

0 292 

0 307 

0.275 

2.510 

2.160 

26.60 

2365 

10  9 

2'  6’ 

J 5 

/'  0 “ 

4 5* 

— 

— 

— 

— 

— 

022 

.121 

.34 

07 

1 

P 

hreroge 

2.646 

8 652 

t.tii 

0.31  1 

O.J27 

0.222 

2.509 

2. 157 

27.70 

239  7 

»•' 

2’  6” 

15 

•»rt 

,,, 

.33 

07, 

R E MARKS 


REMARKS 


dosed  dead) 


9 B»C)  collapstd  at  7/0, 


S i*d  to  IS  SO  pound* 

town  out  af  2335  pcV, 


rne  tooo  / 6 Cage  is  n 
- 3000  It 
-*  8500/6  « <• 

Readings  on  Cages  B o 


Fio.  15. — Tabular  Statement  of  Principal  Results  of  Tests.  Series  1. 


. ,v  .-.iiaavu  >vt3  oraAHDaM  **ak>o8  .M*f  ^oi'toa-  ^hT 

o | s z:\mt. 


O - y.’x  Wtfv  *-a  ~;->wa  -aavi™*  *&  ‘: 

\-.«»  Wav  ■ . .J-vw/:  aW  J'A^-  A-A-'l'i- 

•J'  \tAS»VU»' * V*  ft  »W  W*#  .r.-,-. 


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\ifoW  ’A/v< . ■»»■>!' 


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-.i'8 


Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 

SHOWING  THE  INFLUENCE  OF  OUTSIDE  DIAMETER  AND  THICKNESS  OF  WALL 
.SERIES  2 j ON  COLLAPSING  PRESSURE,  for  lengths  of  20  feet,  between  end  connect, one 
\dmg  to  hold  the  tube  to  a circu/ar  form. 


Reid  T.  Stewart. 

PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 
NATIONAL  TUBE  CO’S.  LAP-WELDEO  BESSEMER  STEEL  TUBES 

CONDUCTED  BY  PROF.  P T S7£WflRT,  1 902-4  F.PK.,UOS. 


Test 

Humber 

Outside  ter 

Thickness 

of  Wall 
ches 

Length  of  Tube 
y Feet 

Weight  of  Tube 
Lbs.  per  Foot 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis  % 

Material 

He: varts 

Commercial  Designation  of 

Tube  as  Reported 

Nominal 

At  Place  of 

Vsmsial 

Average 

At  Place  of 
Collapse 

Reported 

7 / / 

Pounds 

per 

Sq.  Inch 

Cage 

Used 

Pate  of 

Length 

Oistance 

End 

Strength 
Lbs  ptr  Sq  In 

Pounds  ptr 
Square  Inch 

Flongatitn 

T*"h3 

fioduetton 

at  Area 
% 

5, l.con 

Sulphur 

Phos. 

Mang 

Carbon 

Oeida 

Greatest 

Leost 

Greatest 

Least 

Nominal 

b\  ptr  ^ 

In  Feet 

In  Oia’s. 

200 

L,„ 

4 030 

C 123 

0135 

0 104 

10 

11 

m- 

7.77 

450 

2 

3' 

o - 

6 

2'  5i’ 

/ $o* 

*5#  35 0 

*37  470 

9 11  21 

*54.10 



047 

114 

.31 

.00 



b 

4024 

4 OteO 

5.110 

0/27 

0 175 

0.094 

20 

1 7 

'of 

1.0  0 

5 00 

2 

2' 

9" 

5.5 

S'  4" 

+150* 

* 54  220 

* 37  430 

9 17.25 

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— 

.040 

.1 10 

.50 

.00 



ft  b 

4 000 

4.015 

4 030 

5 130 

0 134 

0.130 

0 135 

0.103 

20'  0“ 

20 

11 

<0l 

8 24 

8 11 

575 

B 

2 

3 * 

4" 

7 

2'  4 ' 

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— 

.044 

.105 

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.07 

— 

Oositmer 

' b 

4' Converse  Joint  8.24  Los 

20  3 

4 on 

4 020 

5.140 

0. 130 

0,1 37 

0.1/0 

20 

11 

iar 

8. 1 1 

540 

2 

3 * 

0" 

4 

2'  O' 

-ISO9 

*58  5 30 

*44  140 

91 5.38 

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— 

.059 

.107 

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...  ■ 

Srtti 

b 

204 

4 010 

4.020 

5 140 

0.131 

0.147 

0 1/4 

20 

If 

tay 

8.24 

530 

i 

3 ' 

4“ 

7 

7'  10  " 

0° 

*58  110 

*37  500 

* 18.21 

* 4/43 

— 

.052 

1 10 

.41 

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— 

A.b 

4.0/7 

4 029 

5 144 

0.121 

c.ut 

0.104 

20 

inal- 

S.OI 

511 

i.s 

3 ' Z" 

4.3 

5 8 0 84 

31  47  8 

17.58 

55.2/ 

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101 

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4023 

4.020 

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0.131 

out 

0.101 

20 

11 

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8 22 

530 

2 

3' 

2“ 

4 3 

t 1 

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*51  220 

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C 7 



6 

201 

4.021 

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S 140 

0.121 

0.133 

0.104 

20 

11 

/ oi  * 

8.12 

4-80 

/ 

3‘ 

4" 

7 

3'  0 

180 * 

*41  480 

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9 14.17 

* 50.20 

— 

.057 

.074 

45 

.085 

— 

a 

207 

t,  000 

5110 

5 140 

0.134 

0 134 

0.178 

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*43  420 

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209 

6 013 

4 010 

5.120 

0.135 

0.134 

0.1 10 

20 

If 

toy 

9.45 

510 

2 

2‘ 

1 “ 

5.5 

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*51  710 

9 40  710 

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— 

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.10  7 

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.08 

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b 

207 

4 on 

5.710 

5.910 

0.128 

0. 142 

0.1  !0 

20 

if 

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8.07 

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1 

3' 

3" 

4 5 

7'  0 

180 9 

*54  350 

*39  250 

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— 

.041 

.103 

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— 

b 

Average 

~4  017 

4.002 

S 13  4 

0.131 

0.147 

a. io? 

20 

irni ■ 

8 24 

521 

it 

,■  4" 

47 

51  5 78 

41  942 

ia.ts 

SZ-33 

043 

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AS 

.171 

210 

4.007 

4 020 

5.170 

0.147 

0.178 

0/47 

20 

n 

•*r 

10.44 

1025 

a 

3 

4' 

/- 

8.2 

2'  4" 

- ISO 9 

*58  410 

*44  280 

* 15.75 

*53.70 



074 

105 

09 



211 

4.024 

4.070 

5 .170 

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0.218 

0.141 

20 

n 

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10.51 

130 

8 

5 

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f 

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9 1 i 54 

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— 

071 

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— 

t 

212 

b 000  i 

4.0 1 1 

4.030 

5.190 

0 154 

0.144 

0.174 

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150 

B 

/ 

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8.3 

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9 18.77 

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— 

080 

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6 

SfC.„n,  IbAtlU 

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4.037 

4.050 

5.770 

0 .144 

0 178 

0.115 

20 

n 

10  30 

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2 

4' 

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2'  4 " 

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Srtti 

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214 

4 0)1 

4.030 

5.100 

0.171 

0.177 

0.144 

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nr 

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2 

5 ‘ 

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10 

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*57  140 

*42  320 

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— 

.077 

.109 

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.07 

— 

6 

Hu  *ra9* 

4.022 

4.040 

5 .179 

0.147 

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0.144 

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IT‘ IIS' 

10.4  7 

141 

2.4 

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2" 

8.3 

41  112 

as  in 

15.57 

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210 

4.02$ 

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If 

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07 

— 

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3 

4 ' 

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8 

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4-  10 9 

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— 

■ 084 

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— 

Steel 

t, 

217 

4.021 

4.040 

5.190 

0 /44  \ 

0.191 

0.131 

20 

11 

• oi" 

1031 

180 

2 

4 ' 

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9 

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4 024 

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0.131 

20 

11  'll  " 

10.42 

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7.8 

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AS  328 

15  34 

52  34 

077 

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221 

4 034 

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5 110 

0 It t 

0.141 

0.114 

n 

toy 

10  40 

740 

E 

2 

3. 

4“ 

y 

2‘  0 * 

- ISO 9 

*44  320 

*47 310 

*1425 

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_ 

.084 

III 

31 

a? 

_ 

h 

222 

4 000 

4 037 

4 010 

5 100 

0 154 

0.173 

0.130 

20'  0 - 

20 

/oy 

10  44 

f.7t 

980 

B 

2 

4' 

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1 

2 2“ 

o 9 

*57  470 

*42  540 

* 12.25 

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224 

4.024 

4 040 

5 190 

l.ltt 

0 141 

0.141 

20 

lf 

toy 

IC.40 

I//0 

C 

2 

5 * 

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4 3" 

0 9 

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— 

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35 

aj 

— 

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6 

Average 

4.032 

4 070 

5.757 

0 143 

0.170 

0.131 

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11 

/oi" 

1020 

117 

2 

4' 

2” 

83 

41  443 

45  537 

14.12 

5703 

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223 

4.024 

4.040 

4.000 

0.141 

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0.152 

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11 

r • 

10.54 

1070 

c 

5 

y 

o - 

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4'  0" 

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*57  710 

*43 450 

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085 

104 

.35 

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— 

a 

225 

4 039 

4.050 

5.170 

0 144 

0.1 10 

0.1 17 

20 

11 

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10.31 

7/5 

B 

3 

3 ' 

0 " 

4 

17'  8 ‘ 

- ISO 9 

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• 3$  no 

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— 

044 

018 

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.08 

— 

a 

224 

4.000 

4 029 

4 100 

5.170 

0 154 

0.14 $ 

0.137 

20'  0" 

20 

1 9 

sf 

10.44  ; 

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1425 

C 

4 w 

5 

2 ' 2 ' 

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*41  450 

*13.84 

*53.40 

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.104 

.40 

075 

Btsotmor 

5 J * Caving  / a At  LA,. 

239 

4.037 

5 110 

0.1  47 

0 190 

0.1  to 

20 

n 

if 

10.45 

7 75 

B 

3 

3' 

4 ’ 

7 

2 ' I " 

180 9 

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*17.38 

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— 

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— 

Srtti 

a 

211 

4 034 

4.070 

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0.133 

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10.50 

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c 

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4.044 

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a.nf 

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10.40 

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4.2 

2' 

it’ 

58 

40  144 

AS  7 At 

n, at 

54.34 

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Al 

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Fig.  34.— Tabular  Statement  of  Principal  Results  of  Tests,  Series  2. 


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Transactions  American  Society  op  Mechanical  Engineers,  Vol.  27, 
SERIES  2 


SHOWING  THE  INFLUENCE  OF  OUTSIDE  DIAMETER  AND  THICKNESS  OF  WALL 
ON  COLLAPSING  PRESSURE,  for  lengths  of  20  feet,  between  end  connections 
tending  to  hold  the  tube  to  a circular  form. 


r»r  £ tonparion  Red , 


Reid  T.  Stewart. 

PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 
| NATIONAL  TUBE  CO'S! LAP-WELDED  BESSEMER  STEEL  TUBES 

it-Stewart,  1902-4  FPK,i9oy 


CONDUCTED  L 


Outside  Diameter 

Thicknes 

of*  Wall 

L ength_  of  * Tube. 

Weight  of  Tube 

Lbs.  per  Foot 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis 

Material 

Remarks 

Commercial  Designation  of 

Tube  as  Reported 

Number 

Nominal 

Average 

At  Place  of 
Collapse 

Nominal 

Roerage 

At  PU 
Colt 

opsV 

As 

Pounds 

Sg./nch 

Rate  of 

Length 

'Zo 

Angular 

Distance^ 

Lbs  per  Sq  In. 

Yield  Point 
Pounds  per 
Square  Inch 

Inches 

Reduction 

5,7,t#n 

Sulphur 

Hang. 

Outdo 

Greatest 

Least 

Greatest 

Laa.t 

Nominal 

Actual 

lbs  per  Sec 

In  Feet 

In  Dio’s. 

4 035 

4.050 

5.780 

0 177 

0.174 

a.ui 

20'  0i“ 

lti ■■ 

11.17 

1075 

C 

3 

4‘ 

g 

z'  r 

- 70  ' 

*40  830 

*42  570 

' 14.57 

*53.70 



.070 

.105 

.33 

075 



A 6 

4 021 

4.075 

5.770 

0 217 

0.240 

0.17  8 

20' Oi" 

toy 

13. 57 

1400 

c 

1 

4" 

2'  4" 

*4/  430 

* 47  420 

*18.25 

* 55.00 

.048 

.070 

■36 

.07  5 

* t 

242 

4.035 

4.040 

5.770 

0.220 

0 I8S 

0.177 

0158 

20' 0" 

Zf eh" 

ioi * 

14.20 

/ 1.57 

1272 

C 

3 

0" 

10 

3'  0“ 

*57  170 

*44  200 

*10.76 

*57.70 

.067 

107 

.32 

.065 

Bessemer 

Si' Conn,  to  20  Lb 3 

24  3 

4.034 

4.080 

5.770 

0 170 

0.170 

0.144 

20' Oi" 

17 

ioi' 

10.42 

875 

0 

2 

3‘ 

4’ 

7 

2'  0“ 

+ 70 9 

*41  240 

*44  340 

*14.46 

*56.80 

— 

.076 

.106 

.39 

.075 

— 

Steel 

6 

244 

5.788 

4.020 

5.740 

0.173 

0.253 

0.173 

20‘ Oi" 

17 

ioi ' 

11.77 

1750 

c 

2 

5' 

0" 

10 

17'  4" 

o' 

*41  770 

*41  7 10 

*14.72 

-48.80 

— 

.077 

.101 

.37 

<>■ 

‘ 

6 

ft  ¥9  rage 

4 023 

4.053 

5 774 

0187 

0.215 

0147 

20' oi" 

ir' ioi" 

11.78 

1318 

2 2 

4' 

2" 

8.4 

40  732 

44  854 

15.04 

S4.44o 

.069 

.079 

.36 

.072 

245 

4.040 

5 .780 

0.173 

0.252 

0.174 

20' OK" 

17 

7 • 

11.77 

1375 

c 

5 

4' 

0 " 

8 

17'  0" 

- 20 * 

*41  240 

*40  870 

*15.58 

*55.70 

— 

.080 

.103 

40 

.075 

— 

a 

244 

4-010 

5.930 

0.230 

0.252 

0,197 

2 0’ Oh." 

17 

tT 

14.17 

1700 

c 

5 

3' 

4’ 

7 

2'  I" 

+ 20' 

*45  570 

*49  750 

*16.48 

*51.40 

— 

.081 

.103 

.40 

.07 



a 

247 

0.000 

4.05  5 

5.770 

0.220 

0.1 77 

0.200 

0.153 

20' 0" 

20' Ok" 

ti- 

14.20 

1010 

B 

5 

3' 

O' 

*42  170 

*44  470 

*13.34 

*54.10 

.075 

Bessemer 

Si  C..„,  ,4  20  Lb. 

248 

b.004 

4.040 

5.870 

0.232 

0.243 

0.2/0 

20' 0 ' 

17 

ll' 

14.30 

1800 

C 

5 

4' 

4" 

7 

2'  3" 

~ 20' 

*47  440 

*47  ISO 

*13.13 

* 50.60 

— 

086 

'-107 

.40 

.08 

— 

a 

249 

b.034 

4.050 

5.780 

0.228 

0.237 

0.172 

20' 0 ' 

17 

> 1 ■ 

14.15 

1200 

c 

5 

4' 

4" 

7 

17'  0“ 

-f  IS' 

*45  850 

*48  140 

*16.67 

*5180 

— 

»74 

112 

.35 

075 

— 

A.  a 

Average 

b 021 

4.050 

5.750 

0.212 

0.237 

0.184 

zo'oi' 

If  >3" 

13.16 

1457 

5 

3 ' II" 

7.8 

44  510 

46  724 

15.04  ' 

52  76 

085 

.106 

39 

0 75 

250 

4.014 

4.030 

5.970 

0.172 

0.201 

0.174 

20' 0 “ 

If 

si- 

1 1.74 

1450 

c 

2 

S' 

0" 

10 

3'  6" 

- 5* 

*42  370 

* 46  000 

*16.34 

*5  5.27 

— 

096 

102 

.41 

n 

— 

4p 

251 

4.014 

b.OSO 

5.780 

0.2/4 

0.233 

0.173 

20' Oi" 

si- 

13.25 

1750 

c 

5 

S' 

10 

- io' 

*44  070 

*50  000 

*14.25 

*52.20 

077 

.104 

.075 

252 

4 000 

4 020 

4.050 

5.940 

0.203 

0.222 

0.235 

0.204 

20'  0" 

20' 0 " 

Si' 

12.04 

13.73 

2075 

c 

5 

4 

0" 

12 

3 ' 8" 

* 45 330 

*46  810 

*13.58 

* 47.70 

.072 

too 

.25 

.07 

A,  bP 

5l-C..tn,  12 .04  Lb, 

25  3 

4 020 

b.040 

5.750 

0.184 

0.248 

0.144 

20' oi" 

17 

si' 

1 1.45 

7 SO 

B 

2 

4' 

0" 

8 

7'  7“ 

O' 

' 61  030 

' 47  240 

' 13.50 

*56.00 

— 

.054 

.085 

.40 

.08 

— 

bp 

254 

6.005 

5.750 

0.220 

0.251 

0.201 

20'  oi" 

19 

si' 

13.57 

1550 

C 

2 

S' 

o “ 

10 

15'  4" 

o' 

* 41  870 

* 47550 

*14.27 

•50.40 

— 

.083 

.113 

.40 

.07 

— 

bp 

Average 

4 015 

6.052 

5.744 

0.204 

0.234 

0.187 

zo'o!.' 

17 

5n 

12.80 

155  5 

3.2 

S'  0 * 

10 

42  744 

47  520 

14.37 

52.75 

.083 

.101 

37 

.075 

255 

4.028 

4 050 

5.770 

0.172 

0.208 

0.170 

zo'o  “ 

ti- 

II 78 

770 

0 

2 

3' 

C’ 

7 

2'  O' 

- 45 • 

9 41  410 

*42  720 

*14.72 

*56.10 

— 

.075 

.107 

.38 

.07 

— 

a 

25b 

4.021 

b.OSO 

5 .770 

0.185 

0.175 

0.147 

20'  oi" 

ll' 

II  55 

1450 

c 

5 

4' 

0" 

8 

2'  0“ 

- 20' 

*45  S30 

*48  270 

*15.83 

*56.70 

— 

.086 

.107 

.45 

.075 

— 

a 

257 

4.025 

4.040 

5 .740 

0.203 

0.187 

0.210 

0.145 

20'  0" 

20  ' Oi" 

17 

ti- 

12.04 

1 177 

1250 

c 

3 

0" 

4 

IS'  7 " 

180' 

*43  740 

*46  440 

*14.21 

*55.20 

.051 

.090 

.36 

.07 

Bessemer 

St  Count  It  04  Lb. 

258 

4.013 

4.020 

5.950 

0182 

0.20  7 

0.150 

ZO'O  " 

19 

ll' 

1350 

c 

S 

4' 

0 " 

8 

14'  10“ 

+ 10' 

*57  730 

*44  070 

*13.88 

* 50.40 

— 

.085 

.III 

.35 

.075 

— 

Steel 

■3 

257 

4.024 

6.060 

S.760 

0.182 

0.217 

0.140 

20' 0 • 

17 

11- 

1 1.35 

1100 

c 

3 ' 

o' 

4 

3'  0" 

4-  30' 

*45  540 

9 45  470 

*15.57 

*52.50 

— 

.072 

.107 

.40 

.08  5 

— 

a 

Average 

4.022 

4.043 

5 770 

0.184 

0.208 

0.157 

zo' oi" 

if  «j- 

11.57 

1188 

3 -7 

3'  4" 

7 

43  274 

45  442 

14.87 

54.22 

.074 

.103 

.39 

.075 

210 

4.054 

4.180 

5.720 

0.240 

0.284 

0.242 

20' Oi" 

17 

4i' 

14.06 

1755 

2 

4 

6’ 

7 

17'  6' 

- 10' 

* 40  840 

*41  650 

*17.13 

*55.70 

— 

.078 

.112 

35 

.075 

— 

A.  bp 

2b  1 

4.027 

5.770 

0.251 

0.274 

0.218 

20'  Oi" 

17 

Si- 

15.47 

1750 

2 

4' 

12.5 

10'  3' 

- 10' 

57  3 40 

41  400 

13.38 

57.7  0 

.088 

.33 

.07 

A , bp 

2b2 

4.033 

— 

0271 

0.243 

— 

— 

20' 0" 

ZO'O  * 

19 

Si’ 

14.70 

14.20 

— 

c 

— 

\ 

— 

— 

57  150 

37  480 

22.72 

57.50 

.071 

.34 

rot 

Bessemer 

A .bp 

5j  - Cos.n,  lb.70Lb, 

2b  3 

b.025 

4.040 

5 740 

0.280 

0.300 

0.245 

20' oi" 

17 

54’ 

17.17 

2400 

s 

S' 

o' 

to 

16’  7m 

- 5* 

58  830 

37  140 

17.05 

S4.70 

— 

.074 

.103 

.47 

.075 

— 

Steel 

214 

b.022 

4.080 

4.000 

0.240 

0.272 

0.244 

20' oi" 

17 

si* 

15.77 

2450 

5 

4' 

0 " 

12 

17'  0 * 

O' 

58  050 

36  810 

13.82 

60.50 

— 

085 

.104 

37 

07 

— 

bp 

Average 

b 032 

4.070 

5.748 

0,243 

0.289 

0.242 

20  oi" 

If 

si" 

2137 

3.5 

5' 

5" 

10  7 

.097 

.104 

.38 

.074 

273 

4 021 

4 050 

5.740 

0.270 

0 287 

0.240 

20’ oi" 

1 

ti- 

14.57 

2270 

2 

3' 

8" 

7.3 

18’  O' 

0- 

*43  810 

*47*510 

'18.33 

*5  8.40 

— 

.090 

.101 

.38 

.07 

— 

27b 

6 033 

0.270 

0.224 

20'  oi" 

ll- 

24  75 

5 

4 * 

0’ 

8 

2'  4' 

o' 

'45  830 

9 47  570 

'14.29 

*5  4.00 

.07  7 

.10  7 

42 

277 

6.072 

4.100 

4.000 

0.271 

0.254 

0.304 

0.217 

20'  0" 

20' oi’ 

ii- 

14. 70 

15.77 

2340 

c 

5 

3' 

7.5  . 

18'  0 " 

o' 

57  NO 

37  120 

17.29 

58.30 

.072 

.103 

.37 

.07 

Bessemer 

Sl  C..;,  lb  70  lb. 

282 

b 024 

4 040 

5.770 

0.247 

0.288 

0.230 

20' oi’ 

ti- 

14.44 

2250 

5 

/ ' 

10“ 

3.7 

o’  ir 

o' 

*57  080 

*34  030 

'22.17 

*58.70 

— 

.092 

.106 

.52 

.085 

— 

Steel 

A.  a 

285 

4 022 

4.050 

5.780 

0.270 

0.322 

0 222 

ZO'O  " 

17 

>r 

14.55 

2550 

5 

S' 

O'" 

to 

3'  3" 

4 20' 

*43  440 

*42  ISO 

* 16.33 

*54.80 

— 

■ 075 

HO 

.34 

075 

— 

* 

A v era  fa 

4 034 

5.782 

0.244 

0.277 

0.227 

20  0i~ 

I* 

li.Zi 

2381 

4.4 

3' 

8" 

7.3 

.099 

.109 

.*> 

.076 

Fig.  35. — Tabular  Statement  or  Principal  Results  op  Tests,  Series  2. 


.?£  .joV  ,8aaawo>ia 


,wv»\  i*W»~w  ‘o'V  ••«•, 


Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 

SHOWING  THE.  INFLUENCE  OF  OUTSIDE  DIAMETER  ANO  THICKNESS  OF  WALL 
SERIES  2 l ON  COLLAPSING  PRESSURE,  for  lengths  of  to  foot,  between  end  connection* 

ending  to  ho/d  the  tube  to  a circu/ar  form 


Reid  T.  Stewart. 

PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 
NATIONAL  TUBE  CO’S.  LAP-WELDED  BESSEMER  STEEL  TUBES 

COHOUCTCD  or  FOOF  tt.T.  STCWART.  1*020  FFK.ltbi. 


Test 

Number 

Outside  Diameter 

Thick  ne 

of  Wall 

has 

Length  of  Tube 

y Feet 

Weight  of  Tube 

Lbs.  per  Feet. 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis  y. 

Material 

Pemerhs 

Commercial  Designation  of 

Tube  as  A e ported. 

Nominal 

Average 

At  P! a 
coin 

Greatest 

pee 

Least 

Nominal 

Average 

At  Place  of 
Collapse 

As 

Reported 

Actual 

Sq. Inch 

Gage 

Used 

n.i..t 

L ength 

End 

Tan  si /a 
Strength 
Lbs.  per  S g fn 

Squafe  f?ch 

elc%h!r 

Inches 

vl 

Silicon 

Sulphur 

Hong 

Carbon 

<5 

Greatest 

Least 

AcXvai 

Lbs  par  Sac 

In  Feet 

India's. 

J 00 

4.457 

4.475 

4 SOS 

0 157 

0.125 

01 52 

20 

ok' 

lV7f 

10.87 

7 10 

3 

2' 

0" 

3.4 

2" 

0 * 

* to 9 

55  540 

34  3 10 

21.4  7 

57  20 



047 

10  7 

.38 

.07 



SOI 

4.457 

4.420 

4.595 

0 145 

0 182 

0.145 

20 

08 

!9‘  9s' 

1 / .47 

7 20 

3 

2’ 

4.8 

57  730 

34  530 

21.43 

5 6 20 

.065 

.104 

.39 

075 

a 

so? 

4.025 

4.4S3 

4.705 

4.570 

0.172 

0/42 

0.129 

0 153 

20'  0 " 

20 

/ 9 ’ 9t: 

1 1.42 

a 

3 

2' 

3 4 

58  340 

37  890 

21.82 

60  20 

.059 

HO 

.38 

.08 

Bessemer 

3 03 

4 453 

4.425 

4.575 

0 145 

0.205 

0 145 

20 

17- IK- 

1 1.35 

5 

3 ' 

5.4 

—! /O’ 

57  no 

34  330 

23.04 

5 9.70 

.060 

.090 

.39 

.07 

Stoat 

304 

4.452 

4.425 

4.400 

0.144 

0.214 

0.123 

20 

Or*’ 

II- *4- 

1 1.42 

400 

3' 

0" 

5.4 

2‘ 

180 * 

58  310 

37  520 

22.59 

56.60 

— 

.068 

.108 

.38 

.075 

— 

4 

Or.ro,. 

4 454 

4.424 

l.Sl* 

•■it* 

0.194 

0.144 

20 

ei’ 

19-  rr 

11.35 

Lit 

3.4 

2'  4" 

*.L 

57  4/f 

34  5 14 

tz.lt 

58.02 

.014 

104 

SI 

.074 

305 

4.420  , 

4.725 

4.405 

0.194 

0.220 

0.120 

20 

Os' 

nil' 

13.57 

i too 

J 

2’ 

0 * 

3.4 

2' 

# 

o * 

59  790 

34  200 

23.21 

57. !0 

— 

.048 

112 

.37 

.09 



m 

3 01 

4.493 

4.700 

4.590 

0.200 

0.207 

0 194 

20 

0 " 

I9‘  9f 

13.85 

1205 

4 

3' 

0“ 

5.4 

2' 

4’ 

O' 

57  770 

34  030 

If.  84 

42.30 

— 

051 

■ 108 

•Jt 

.065 

— 

a 

307 

4.125 

4.705 

4.545 

0.203 

0.202 

0 227 

0.124 

20'  0 ' 

20 

or 

If  8s’ 

13.32 

13.99 

1275 

c 

5 

2' 

4 " 

4.5 

4 10* 

57  070 

33  720 

22.42 

60. SO 

.054 

.075 

Bessemer 

6k'  Casing  13. 32  Lbs 

3 ot 

4 427 

4.47  0 

4.575 

0.205 

0.225 

0.200 

20 

or 

I9‘ 

14.17 

1245 

S 

3 ' 

0 - 

5.4 

17' 

4" 

0 * 

57  100 

34  090 

24.42 

61.70 

— 

064 

.102 

.37 

075 

— 

Steal 

309 

4 474 

4.475 

4.570 

0.194 

— 

— 

20 

0 " 

/9‘7hr 

1 3.57 

1075 

* 

* 

0” 

5.4 

7‘ 

57  490 

35  970 

23.42 

57.90 

— 

.06/ 

078 

. Jf 

.07 

— 

m 

Mu  a rage 

4.424 

4.495 

4.521 

0.200 

0.220 

0 .190 

20 ’ Or: 

/9'  7 ;J: 

13.83 

' 184 

4.2 

2'  8’ 

4 9 

57  248 

35  402 

22.46 

5 5.94 

■ 060 

105 

38 

.075 

310 

4 44/ 

4.440 

4.410 

0.240 

0.272 

0.245 

20 

Or: 

Hi «- 

17.74 

2275 

5 

3' 

0 " 

5.4 

2' 

4” 

0* 

57  590 

35  930 

24/3 

59.90 



.055 

too 

.39 

.07 



Bess  Steal 

P e 

ill 

4.474 

4.455 

4.40  5 

0.254 

0.277 

0.225 

20 

or 

17.39 

2140 

5 

4 ' 

4* 

7 3 

2 ' 

O’ 

4 to* 

57  49 0 

34  4/0 

25.33 

6 0.80 

— 

.06  7 

.1 16- 

.34 

.07 

— 

P.A 

4.425 

4.449 

4.445 

4.520 

0.232 

0.252 

0.244 

0.224 

20'  0" 

17.02 

17.25 

1975 

5 

3 ' 

5 4 

4 15* 

54  340 

32  740 

20.42 

62.60 

.071 

106 

.37 

CIS 

Li"  Cas.no  17  02  Us 

313 

4.457 

4.415 

4 555 

0.250 

— 

— 

20 

or 

/9‘8i” 

17.09 

1820 

5 

2' 

*' 

4.5 

18' 

0 “ 

180* 

47  /JO 

33  220 

13.09 

23.10 

— 

.0/5 

1 9 6 

Trace 

Trace 

— 

Wra-t  han 

n a 

314 

4 471 

4 450 

4.595 

0.251 

0.22  3 

0.228 

20 

0 

•9  '/or 

17.20 

2/75 

5 

3' 

8“ 

5.4 

13' 

4" 

0* 

57  no 

34  480 

2179 

60.40 

— 

.05  4 

.100 

.37 

.07 

— 

Bets.  Steel 

a 

3IS 

7.044 

7.070 

7.000 

0 158 

0.177 

0.122 

20 

or 

if  u- 

11.41 

570 

4 

2‘ 

4 * 

4.3 

9‘ 

4" 

4 15* 

57  430 

38  510 

17.92 

54.50 

— 

053 

Of j 

.34 

.07 



314 

7.040 

7.075 

4.995 

0.158 

0.177 

0.134 

20 

or 

11‘lf 

1 1.58 

550 

4 

2' 

0 " 

3.4 

%’ 

4 " 

0 * 

54  440 

35  280 

21.1  7 

5 9.70 

— 

.057 

/ 06 

.35 

07 

— 

a 

317 

7 000 

7.043 

7.090 

4.990 

0180 

0.1 54 

0.170 

0.122 

20'  0" 

20 

II- ti- 

12.34 

1 1.31 

575 

e 

3 

0 " 

3.4 

IS' 

8 * 

0* 

54  850 

36  7 80 

16.7 1 

61  60 

— 

056 

.095 

.075 

— 

Bessemer 

a 

L>-  Casing  12  34  Lb s. 

3 1/ 

7 0 33 

7 .040 

4.920 

0.214 

0.13  5 

ok" 

ll'  If 

12.1 3 

5 80 

3 

2 ' 

4.0 

0* 

59  520 

41  140 

22.42 

52.90 

.069 

.37 

.07 

Steal 

319 

7.059 

7.075 

4.995 

0/43 

0.217 

0.130 

20 

or 

a- w 

11.94 

S 40 

5 

2 ' 

0 " 

3.4 

14' 

*" 

- 120 * 

54  070 

38  920 

19.25 

58.30 

— 

.059 

.106 

.36 

.08 

— 

e. 

1 044 

7.070 

L.no 

0.140 

0.191 

0.130 

20 

or 

ii-  H- 

11.72 

5*3 

3.8 

2' 

2* 

3.7 

57  242 

38  246 

11.41 

57.40 

.059 

.101 

■ St 

.0  73 

320 

7.050 

7 .025 

4 990 

0.245 

0.257 

0.225 

20 

or 

’f  ti- 

17.74 

<775 

* 

2' 

4* 

4.0 

9' 

9 * 

0* 

59  840 

37  220 

21.94 

51.30 

— 

.072 

.110 

.35 

075 



*.* 

321 

7.050 

7.070 

4.920 

0.241 

0.273 

0.220 

20 

0 " 

ll- H’ 

17.50 

1 575 

4 

2' 

4 • 

4.3 

3' 

0 * 

4 15* 

59  440 

32  250 

213) 

56.30 

— 

.065 

■ 101 

.39 

.07 

— - 

a 

322 

7.000 

*1.057 

7.020 

4.920 

0.242 

0.243 

0.202 

20'  0" 

0 " 

1’’ it" 

17.51 

14.9  7 

1525 

c 

5 

2' 

4.6 

S' 

0* 

57  730 

35  500 

23.34 

57.90 

.06  1 

.094 

.38 

07 

Basse  mar 

Li ' Casing  i7.St  Lb. 

323 

7 045 

7.090 

4.920 

0.245 

0.270 

0.220 

20 

or 

a T 

17.77 

1475 

5 

3' 

o~ 

5.1 

2' 

4’ 

180* 

40  210 

33  910 

23.50 

56. Lf 

— 

.06  1 

.102 

.37 

.0  75 

— 

Steel 

a 

324 

7.047 

7.020 

4.990 

0 242 

0 241 

0.204 

20 

or 

17- • i " 

18.02 

1850 

5 

2 ' 

4" 

4.3 

r 

4m 

0* 

57  720 

35  730 

24.7/ 

57.30 

— 

.060 

.100 

.37 

.07 

— 

*.<* 

Buarag'e 

7 050 

7 081 

4.984 

0.242 

0.241 

0.2/4 

20'  ok" 

ii- tf 

\480 

44 

2'  T 

4.5 

59  036 

36  134 

22.97 

55-7  8 

.064 

.101 

.37 

ci; 

400 

4.443 

4.750 

4.540 

0.1 54 

0.1 59 

0.1  to 

20 

/t 

ii'  fi- 

10.48 

*400 

*10 

*20’ 

0’ 

* 342 

/S' 

i ■ 

tew* 

58  260 

44  83  5 

13.21 

51.10 



.061 

089 

.37 

.07 



P.e 

401 

4.452 

4.730 

0.520 

0.157 

0.190 

0.130 

20 

or 

ll'  >r 

10.87 

585 

3 

4" 

8.2 

5' 

3" 

4-150 m 

52  78 5 

37  565 

15.50 

53.90 

— 

.058 

.090 

.33 

.07 

— 

c 

4.445 

4.7  30 

4.520 

0 ISO 

0/52 

0.142 

0125 

20'  0 * 

li- 

10.39 

10.57 

585 

0 

3 

4' 

9“ 

8.4 

7' 

0" 

4140* 

574/5 

37  025 

21.00 

57.10 

— 

.070 

.105 

.35 

.07 

— 

Bessemer 

c 

Specs!  Li' OP  10  31  Lbs. 

4-441 

4.71 0 

. 4.570 

0154 

0.122 

0.140 

3 0 

ck' 

ii-  ti- 

10.47 

540 

3 

S' 

/0.0 

4‘ 

0 " 

58  385 

38  035 

21.72 

60.10 

.0  75 

.IIS 

.07 

Steel 

4.457 

4.720 

4.590 

0.153 

0.173 

0.125 

zo 

Ob’ 

ll'  U- 

10.59 

520 

2 

4 ' 

4" 

8.2 

15' 

0“ 

0* 

54  445 

35  495 

20.46 

54.20 

— 

.070 

.107 

32 

0 7 

— 

« 

‘ 

4.722 

4 574 

0.1 54 

0.173 

e.iLi 

20 

o}~ 

n-i  " 

IC.tt 

543 

2.8 

a-  if 

8.8 

54  458 

39  031 

18.42 

5 5.28 

.on 

.101 

■ S4 

.07 

Fig.  36. — Tabular  Statement  of  Principal  Results  of  Tests,  Series  2. 


• ■ ' ' ■ 


^ Y>  - ■-  V'.  ■••>  ™ ■-■'•■  . ; ■':  ■ ..  ) 

■ ..  . ■•  •-  •**  > 


L-.  • .;  ■ * j 

V.1JV  ' 

-•- - — v — — —t*  i 

;•«  ! «'•  • , ••• ; *“  i 

at*  * ■ vu  * ' ; 


Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 

SHOWING  THE  INFLUENCE  OF  OUTSIDE  DIAMETER  AND  THICKNESS  OF  WAIL 
SERIES  2 { ON  COLLAPSING  PRESSURE,  for  lengths  of  TO  feet,  between  end  connection s 

id  mg  to  ho/d  the  to  bo  to  a circular  form. 


ere/  hetTfoot.  She 


Reid  T.  Stewart. 

PRINCIPAL  RESULTS  OE  COLLAPSING  TESTS  ON 
NATIONAL  TUBE  COS.  LAP  WELOEO  BESSEMER  STEEL  TUBES 
conouctco  or  pnof.  at  stcmpt,  1902- 


Test 

Outside  O/omeler 

Thickness 

of  Wall 

Lengt^of*  Tube 

Weight  of  Tube 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis  JS 

mini 

Average 

At  P/a 

r ,m. 

Average 

fit  Place  of 
Collapse 

fis 



Lbs  />« 

rt... 

Pounds 

Gage 

Rate  of 

Length 

O.xta 

me. 

Tenmile 

|] 

Rad yet,  an 

Material 

Commercial  Designation 

Greatest 

Greatest 

Least 

Reported 

No  mi  no / 

s/toch 

Used 

In  Feet 

ere 

18‘P~%  *• 

Sqvere  inch 

"ET 

*fAraa 

Sulphur 

H.ny 

<W. 

Tab.  as  Rap  or  fed 

40  s 

4.45  0 

5.700 

ls„ 

0.252 

0 211 

0 2/5 

20-  /.{• 

/ 7 * mm 

it.ts 

2/35 

J 

y 

6' 

83 

2' 

0 - 

no" 

56  4/5 

38  430 

20.54 

44  20 



.05  9 

.107 

31 

07 

e 

40  4 

6 4 5 3 

5.580 

0 282 

0 303 

20'  hi" 

17. 85 

1175 

4 

15' 

om 

57  340 

37  120 

/ 7 46 

55.10 

.052 

.075 

40  7 

4.454- 

5.700 

0 290 

0.210 

0 247 

20'  O' 

20'  2 

nioi" 

18.78, 

19.14 

2580 

3 

S' 

6' 

10  0 

2' 

O' 

- 154 * 

57  725 

34  455 

25  2/ 

80.50 



^03# 

■ 085 

.33 



Bessemer 

c 

8‘ Fell  We-  At  18  78  L 

408 

4.4  51 

5.570 

6.6/0 

0.251 

0 277 

0.230 

20'  li" 

if  ef 

17.81 

2080 

3 

4’ 

6' 

8 1 

12' 

0" 

-f  37* 

55  525 

34  84 5 

11.08 

42.50 

— 

.100 

.07 



Sr  a*/ 

c 

g os 

401 

4 44 4 

4 510 

4. 600 

0 284 

0.325 

0 272 

20'  Oi" 

n'»i" 

11.35 

2340 

' 

S' 

O' 

It 

>7' 

0 ‘ 

+ 13* 

5#  465 

38  195 

25.33 

58  30 

— 

089 

3* 

.075 

— 

c 

6.455 

6.48? 

0.251 

0.217 

0.242 

io‘  li • 

ifti" 

II.3S. 

22/4 

i > 

4- 

7" 

>* 

57  <74 

35  801 

2/72 

52.12 

05/ 

m 

.34 

0 7 o' 

410 

4 484 

4 73  0 

6 570 

0.241 

0-257 

0.220 

20'  li' 

11’  If 

18.51 

1880 

5 

4' 

0 * 

7.3 

10' 

0" 

+ 50* 

55  180 

38  710 

2/  25 

S3. 10 

— 

.077 

105 

32 

.07 



c 

41  1 

4 684 

6 700 

6.630 

0.252 

0.217 

0.217 

20’  if 

11'  if 

17.24 

1940 

2 

6 ’ 

0" 

10.1 

8' 

o'" 

- 43* 

57  J#0 

35  465 

21  84 

58  80 

— 

.074 

102 

36 

.0  75 



c 

4/2 

6 675 

0.23# 

0.258 

0.301 

0.224 

20'  0" 

11'  If 

17.02 

17.5/ 

1780 

C 

3 

S' 

0 " 

- 180 * 

5#  395 

37  375 

24.48 

51.50 

.077 

100 

.07 

Bessemer 

8*' Casing  1 7 02  Lbs 

413 

6.47 1 

0.248 

0.28  3 

0.223 

20‘  li’ 

11  If 

18.71 

/ 7/0 

2 

S' 

8" 

10  0 

7* 

6" 

+ 45* 

58  715 

34  #30 

20.38 

57.30 

— 

.072 

.017 

.31 

.07 



Sveel 

c 

414 

6 582 

6 7 00 

6 600 

0.248 

0 282 

0.217 

20'  if 

11'  If 

17.01 

1815 

8' 

om 

10.1 

18' 

8’ 

4 70* 

55  775 

3#  180 

20.25 

81  00 

— 

.080 

.103 

32 

.07 

— 

c 

Average 

6 4 81 

5 710 

4.604 

0.241 

0.282 

0.220 

20'  li" 

11'  If 

17.07 

1745 

3.2 

5' 

4" 

9.8 

58  841 

37  128 

21.84 

57.14 

078 

.101 

3 3 

07 1 

4/5 

6 072 

6 030 

0.250 

0.277 

0.203 

20'  li" 

if  ti- 

IS. 53 

2220 

3 

4 

6* 

1.0 

18' 

o • 

_ 20» 

55  90S 

38  885 

11.13 

80  10 



092 

Oil 

34 

075 



c 

4/5 

6 .042 

5 050 

5 000 

0.282 

0.277 

0.208 

20'  If 

18.18 

2555 

2 

4' 

8" 

1.0 

13' 

0“ 

8 75° 

57  235 

38  255 

21  SO 

81.70 

— 

078 

108 

35 

.07 



C 

4/7 

4 .000 

5 080 

5.000 

0 27/ 

0 271 

0.307 

0 222 

20'  0" 

20 • li" 

if  si" 

18.70 

2400 

c 

/ 

12.0 

4 7i* 

5#  245 

39  185 

22.93 

51  80 

.083 

104 

32 

.07 

si"  Caving  IS  TO  Lbs. 

41 1 

5 080 

6 020 

0.2  77 

0.307 

0.244 

20-  If 

• r ni- 

17.08 

2270 

5 

* 

O' 

12.0 

3 ' 

0“ 

-170* 

54  720 

38  005 

22  3# 

58.10 

— 

.095 

108 

.35 

.07 

— 

c 

41  f 

6 044 

6 060 

0.27/ 

0.313 

0.113 

20'  li" 

if  ti- 

18.73 

2575 

* 

5' 

0" 

10.0 

7* 

0" 

~ 85* 

5#  445 

37  475 

17  08 

57  80 

— 

.010 

105 

.27 

— 

C 

*»•'«». 

6 047 

6 076 

6 0/2 

0.288 

0.217 

0.2/4 

20'  If 

If '/Of 

1 0.44 

25 22 

3 

S' 

2" 

!0.4 

57  330 

37  773 

20  ft 

51.28 

083 

.104 

J3 

.071 

1 

8 857 

— 

— 

0.178 

0.17  0 

0/70 

20.120 

11.818 

15.12 

450 

— 

8 ' 

0" 

8.3 

II' 

0" 

- 18* 

58  4/0 

35  470 

28  13 

57  SO 

005 

081 

101 

.35 

ot 

— 

l 

f 637 

— 

— 

0 111 

0 115 

0.171 

11.918 

11  818 

17.24 

825 

— 

6 ' 

3" 

8.7 

IS' 

8" 

- 30* 

80  410 

3#  030 

2 1 04 

57.20 

008 

077 

.118 

.32 

075 

■ 

These  Rttt 

3 

2 425 

7 64 / 

— 

— 

0.1 80 

0.188 

0 184 

0 189 

20’  0' 

11.117 

11.815 

1807 

1877 

535 

5 

— 

S' 

6' 

7.7 

4' 

3* 

■8120* 

80  020 

38  420 

24  00 

58.73 

008 

077 

.31 

0 75 

— 

Bass  tmar 

reeled  eam 

li" Casing  10.07  Lbs 

4 

8 540 

— 

— 

0 183 

0.11 1 

0.171 

20.004 

11 .702 

18.54 

450 

— 

S' 

8" 

7.7 

1 5* 

3" 

- 30* 

58  840 

35  510 

2 / 72 

514J 

008 

071 

.32 

\ 09 

— 

Sraal 

Senes  1. 

s 

8 538 

— 

— 

o in 

0.117 

01 73 

20.01  1 

17.23 

820 

— 

S' 

0" 

7.0 

4 ‘ 

7" 

■6  /5® 

51  180 

38  350 

23  00 

51.50 

.010 

.087 

3 1 

.0  75 

— 

Average 

8 643 

0 185 

cm 

0.172 

20.028 

If  74 

538 

5' 

8'' 

7.1 

SI  344 

Jo  j to 

23  22 

58.53 

.007 

074 

no 

32 

.077 

24 

2 604 

8.510 

8-580 

0.211 

0 230 

0.210 

11'  2 " 

11/88 

18  888 

11.57 

270 

e 



S’ 

6* 

7 7 

14' 

10” 

- 5#* 

58  700 

34  080 

22  77 

51  40 

008 

.04# 

105 

3# 

07 

— 

27 

2 529 

8 540 

8 510 

0.2  33 

0 231 

0 188 

13'  8" 

13.87$ 

13.373 

20  IS 

1 l 15 

c 

— 

s’ 

6* 

7.7 

10' 

1 * 

- f • 

57  770 

34  730 

22.33 

53  70 

.070 

.102 

.32 

.075 

— 

re*,.  n*n 

28 

8 525 

t 457 

2.550 

8.530 

0 221 

0 213 

0 222 

It'll  | 

12  132 

12.830 

20  10 

<723 

250 

8 

S' 

7.7 

8' 

2* 

- 67* 

80  5 30 

37  7 00 

/ 6.67 

57  20 

.1 17 

.35 

08 

Bessemer 

ttpledbem 

8*  Cosing  20  10  Lbs 

21 

8 510 

9 520 

0 213 

0 22 1 

0.180 

1 2 8' 

12.874 

12.372 

11  18 

750 

B 

1.4 

5' 

f 

7.7 

r 

-145* 

si  no 

37  300 

23  47 

57.70 

— 

.089 

.45 

08 

— 

Steel 

Sene s 1 

30 

8 570 

2.510 

2 440 

0.117 

0.21  I 

0 175 

12  3’ 

It  252 

II  ISO 

17  71 

650 

B 

1 4 

S' 

8" 

7.7 

4' 

2* 

- 58* 

80  850 

37  580 

20.71 

55.70 

004 

088 

.1  10 

37 

075 

— 

keeroge 

2.5S9 

2 520 

0.21 5 

0.22  5 

0/21 

If.  34 

847 

/ .4 

s' 

6“ 

7.7 

51404 

38  270 

21.23 

57.14 

.072 

.109 

38 

078 

SO 

8.550 

#•605 

2 585 

0 27/ 

0 227 

0 265 

20.000 

11.848 

24  28 

1435 

4 1 

S’ 

*• 

7 7 

18' 

10“ 

+ 22* 

58  220 

34  120 

23  75 

57  10 

004 

.070 

112 

.35 

.02 

— 

51 

8 529 

#7/5 

8 80S 

0 274 

0 220 

0 288 

11.188 

If  834 

24  5 4 

1430 

6 2 

0" 

2 4 

9' 

2" 

-ISO* 

59  810 

37  300 

20  12 

54.70 



084 

105 

.075 

rh.se  r.,rt 

52 

ti  * Cosing  24  3#  Lbs 

53 

8 550 

8.3  75 

2 825 

0.272 

0 282 

0 255 

/ 7.772 

>1  838 

23.  / 3 
24  32 

1520 

4 \ 

S’ 

7 7 

"• 

3" 

- 6#® 

58  85 0 

34  300 

24  13 

5 7 t0 

1 

085 

'07 

.27 

04 

— 

Steel 

S4 

t 550 

f 645 

0.282 

0 220 

0 25  5 

/ 1.113 

li  831 

23.52 

1485 

5 2 

8 ’ 

0" 

8 4 

7* 

5" 

-ISO* 

57  5 00 

35  #00 

20  71 

51  90 

— 

.073 

101 

.38 

— 

Rue  nag* 

2 555 

#4#7 

0 287 

0 272 

0.258 

nets 

itici 

23.18 

1438 

4 7 

S'  7“ 

,0 

58  378 

35  700 

22.48 

57.88 

.077 

lot 

33 

.077 

Fig.  37. — Tabular  Statement  of  Principal  Results  of  Tests,  Series  2. 


, n*  \*  *Mw*V  ^ ; iv>  . 

«sa«>  M»Wv\o  «>  ‘i1'  V.O*  "'  V ' -•'■•*'' 


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Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 

SHOWING  THE  INFLUENCE  OF  OUTSIDE  DIAMETER  AND  THICKNESS  OF  WALL 
SERIES  2 ( ON  COLLAPSING  PRESSURE,  for  lengths  of  20  foot,  hero/oen  on*  connections 


Reid  T.  Stewart. 

PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 
NATIONAL  TUBE  COS.  LAP-WELDED  BESSEMER  STEEL  TUBES 

COMOUCTIO  BY  PR  Of  R.T  STEWART,  1901-4  PPK  tfOf 


Test 

Number 

Outside  Diameter 

Thickness 

of  Wall 

L ength  of  Tube 

Weight  of  Tube 

Collapsing  Pressure 

Collapsed  Port /on 

Physical  Properties 

Chemical  Analysis  % 

Materia/ 

Commercial  Designation  et 

Tube  as  Paper  ted 

Nominal 

Average 

At  Place  of 

Co  Hap** 

Nominal 

Average 

At  Place  of 

A* 

Pa ported 



SqZch 

Gaga 

Used 

na,..f 

L ength 

End 

O.sfanca 
from  Weld 

Strength 
lb*  per  Sf/n. 

Square  Inch 

Reduchen 

Silicon 

Sulphur 

Phes 

Meng 

On  dr 

Creates/ 

Last 

Greatest 

Least 

Mamina/ 

Actual 

In  Peat 

In  Dio's 

75 

9.540 

9 375 

,.„5 

0 274 

1.212 

0 250 

10-  0- 

20  003 

nut 

24  4 4 

1375 

4, 

3'  3" 

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r 

* ».• 

55  380 

32  880 

24.54 

31.00 

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Oil 

101 

35 

ot 



fl«it  Steel 

74 

9 533 

8.595 

8 3 55 

0 272 

0 212 

0.271 

20  0" 

• 1.189 

11  834 

24  3 8 

1410 

3 4 

— 

— 

1 4 ' 

1 l" 

■f  40* 

51  210 

35  530 

19.33 

58.00 

— 

085 

103 

40 

08 

___ 

Thete  TV  in 

77 

242  5 

9 550 

9 335 

9.30  5 

0 291 

0.2  74 

0)11 

0.232 

11  10 ' 

1 1.8  55 

11  501 

25  00 

24.47 

127  5 

C 

7 3 

f 1" 

to  9 

1' 

5* 

-120' 

A3  7 40 

25  240 

15.21 

29.30 

— 

0/1 

147 

Tree a 

Trace 

/ 49 

Wre’t  Iren 

cap, re  tram 

1 * Line  Pipe  2S  00  Lbs 

79 

9 550 

8 700 

8 SIS 

0 280 

0 214 

0 2 74 

19  1 ’ 

18.315 

25.08 

1250 

1 5 

7 ' O' 

1 7 

1' 

3" 

■f  12 ' 

45  3/0 

25.30 

.054 

.0)2 

110 

.1 1 

■ 08  S 

2 59 

3er.es  J 

73 

9 534 

t 370 

9 350 

0 235 

0 290 

0.243 

19  4 - 

18.340 

17.183 

23  24 

1425 

9.5 

3’  3’ 

10 

IS' 

3“ 

— #35* 

43  430 

23  7/0 

1512 

28.90 

082 

040 

101 

' i 

.08  5 

1 72 

/ 

99 

9 935 

9 380 

8 34  5 

0 308 

0.312 

0213 

11  910 

11.333 

27  44 

1 735 

5.5 

3'  3" 

9.7 

14' 

10" 

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55  390 

22  830 

2 7 13 

35.30 

— 

.020 

022 

.40 

14 

— 

oh  Steel 

IT 

3.333 

8 700 

8 320 

0 234 

0.287 

0.252 

20  000 

19  848 

23  38 

13  75 

5.4 

— 

l ' 

7" 

1 90  ' 

59  010 

33  330 

24  43 

30.20 

... 

.051 

1 13 

.35 

■ 0 75 

— 

Bess  - 

these  tes's 

100 

9 92  5 

9 335 

9 3/5 

0 322 

0 217 

0.319 

0.300 

20'  O' 

11.171 

H 845 

22/77 

28  44 

C 

1.  7 

V 

4 18 ' 

S3  350 

34  5 10 

23  75 

51.30 

.087 

112 

33 

.08 

cap  tee  Emm 

9"  Line  Pipe  29.111  Lbs 

10  1 

9.347 

9 705 

9 535 

0 214 

0.217 

0 252 

11  775 

11  84/ 

23  27 

1350 

7.0 

5'  0 9 

9 4 

1 7 ' 

4" 

■f/  12 * 

51  300 

35  510 

84.54 

5 180 

— 

.074 

10  5 

.35 

07 

— 

- 

3er.es  2. 

102 

9.553 

2.375 

0 303 

0.3/2 

0 283 

20.0/2 

11.358 

27.00 

1180 

5 4 

S'  1' 

to 

13' 

2" 

-130* 

80  130 

37  410 

23  87 

53.90 

— 

085 

.102 

40 

02 

— 

.. 

420 

9 351 

2.700 

9.3/0 

0 310 

0.350 

0 251 

20-  li- 

11 ioi" 

27  34 

1805 

4 

S'  0" 

7.0 

• S' 

0 • 

4 25' 

53  325 

33  130 

21  89 

51  SO 

— 

.034 

101 

34 

07 

— 

c 

421 

9 399 

9.310 

0.303 

0.350 

0.231 

• i ' ii' 

2701 

1135 

5 

5'  3" 

7.7 

14' 

8" 

4 20 ' 

55  405 

35  / 10 

23  00 

51  30 

— 

.032 

107 

32 

075 

— 

c 

422 

2.525 

9.372 

8 730 

8.300 

0 3 22 

0.307 

0 403 

0.277 

20  O' 

lt  ■ oV 

ii'  iK 

29.18 

27  31 

1535 

c 

3 

5 ' O' 

S 3 

I l 

3" 

■f  5 O' 

58  115 

35  725 

21.75 

5 8.00 

— 

.030 

.104 

.33 

.07 

— 

Bessemer 

c 

9'  full  Weight  *9  '9  Lb I 

423 

I 947 

9 710 

2 3/0 

0 325 

0 255 

21  ’ Cf 

27  00 

4 

8.3 

0 9 

- 25' 

51  195 

31  305 

23  33 

57.20 

070 

Steel 

424 

9.371 

9. 730 

8 5 70 

0.302 

0 322 

0-253 

20'  2 " 

n'/oV 

23  18 

1575 

3 

5'  0‘ 

9 3 

II 

0 ' 

- 25' 

57  215 

35  730 

2 1 09 

57  20 

— 

.031 

1/3 

.34 

.07 

— 

« 

A,ere,e 

9 333 

2.7/2 

8 304 

0 305 

0.353 

0 251 

20-  if 

ir  nr 

27.22 

1 753 

3.1 

5'  f 

7.1 

57  431 

35  1 94 

22  21 

53  84 

.083 

.101 

33 

■ 071 

425 

9 888 

9 390 

8 330 

0.341 

0.327 

0.321 

20  ■ of 

— 

31  00 

2 190 

2 

5'  0" 

7.0 

2 1 

0" 

- 45' 

44  770 

3/  545 

8 38 

24  80 

— 

.020 

283 

Tree  a 

Trece 

— 

C 

420 

9 572 

9.300 

0.334 

0 405 

0.340 

20  ' if 

32.30 

2/5  5 

2 

5'  0" 

7.0 

o' 

- 95' 

50  345 

33  925 

IS.  84 

27  00 

.022 

Tree  a 

427 

9.579 

9.7/0 

2 350 

0.333 

0 343 

0.315 

0.343 

20‘  0 ' 

20’  Of 

If  91" 

32  00 

30  82 

1830 

c 

j 

S'  f 

7.7 

17' 

0 9 

~/3S ' 

45  385 

21  200 

18  75 

25.70 

— 

.0/9 

.101 

Tree e 

Trace 

— 

Wreughr 

c 

9 0. t We//  Tubing  32  00 Us. 

429 

9.554 

9.7/0 

8.3/0 

0.353 

0.420 

0.317 

20-  if 

if'/oi’ 

3/35 

2045 

3 

4'  0 ‘ 

S3 

It' 

4" 

-/OS' 

31  880 

21  70S 

7.25 

22.80 

— 

.020 

.253 

Treea 

Trece 

— 

/ten 

c 

423 

9.393 

9.730 

9.330 

0.353 

— 

— 

20  ‘ Of 

31.52 

1130 

4 

S'  3" 

7.7 

15' 

3" 

4 MS' 

44  730 

29  77 0 

11.12 

33.30 

— 

.01 7 

.133 

Treee 

Trace 

— 

C 

Peerage 

9.573 

9.  709 

8 .324 

0.354 

0.402 

0.330 

20  r 

• i it 

3/42 

2028 

2.8 

5'  0" 

70 

45  034 

30  309 

14  13 

23.79 

.0/1 

.208 

Trmee 

Trece 

430 

3 794 

7 020 

3 150 

0.210 

0.323 

0.234 

20  ' 28" 

/not 

20  74 

2445 

4 

4 • t- 

77 

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3" 

o* 

33  115 

41  5 85 

24.83 

54.00 



.052 

124 

.30 

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— 

e 

4 31 

3.175 

7.000 

3 120 

0293 

0.322 

0.247 

20'  2" 

20.23 

2300 

1 

5'  3" 

14 

17' 

0" 

O' 

57  135 

34  845 

25.59 

57.30 

— 

.0  57 

107 

.30 

.07 

— 

c 

432 

7 000 

7.0  19 

7 030 

3 190 

0 290 

0238 

0 345 

0.225 

20'  2‘ 

20'  29" 

if/ot 

20.12 

11.33 

1835 

c 

3 

4'  3" 

0" 

57  540 

35  575 

22.08 

51.40 

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Bessemer 

Specie/  TOD  20-/2' Lbs. 

433 

3.174 

7 000 

5 120 

0 287 

0 325 

0 255 

20'  2i" 

if/ot 

20.47 

2/80 

2 

3'  0 "■ 

10  0 

1 ' 

0 * 

- 10 • 

S1 155 

35  300 

24.83 

59.30 

— 

.033 

118 

.32 

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— 

Steel 

c 

434 

3.194 

7.020 

5.140 

0.231 

0.320 

0.235 

20'  2 " 

/l' /oi" 

11.34 

1175 

4 

4'  0 ' 

3.1 

If 

0" 

4170 ' 

30  740 

39  490 

23.13 

59  SO 

— 

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21 

0 75 

— 

<■ 

Pearege 

3.197 

7.020 

3 142 

0 271 

0 327 

0 245 

20  ' 2-; 

tof 

20  02 

2147 

2.9 

4/1" 

9.3 

80  023 

37  2/7 

24.23 

51  53 

058 

.11 7 

.31 

071 

435 

7 009 

7 050 

3 110 

013/ 

0.175 

0.149 

/ / .75 

335 

4 

4'  3" 

77 

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4" 

4130 ' 

30  445 

31  580 

20  93 

5 2.30 

— 

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.31 

.07 

— 

C 

4J3 

7 0/5 

0./38 

0 232 

0.14) 

20'  2" 

n'/ot 

12.25 

34S 

5 

S'  3" 

1.4 

4* 

o" 

- 75* 

58  425 

37  805 

2/.I3 

5 7 00 

— 

.080 

.33 

.07 

— 

C 

437 

7 000 

0.1  SO 

0.155 

0/92 

0 133 

20‘  2~ 

20'  2" 

90.85 

1 1.3/ 

505 

a 

2 

4'  3" 

7 7 

0" 

4120' 

51  115 

38  420 

20.08 

a. io 

.073 

.122 

.34 

.075 

Bessemer 

1“  Centre rse  Print  /$  85  LBS. 

439 

7.0/5 

7.070 

0.132 

0/8  5 

0./3S 

20'  2" 

/ 1 ' /oi" 

i its 

375 

5 

S'  0" 

8.3 

17' 

4' 

- 7 O' 

58  7/5 

38  100 

23  00 

53.30 

— 

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.32 

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- ■ 

Steel 

c 

433 

7 001 

7/00 

3 130 

0./S3 

0.173 

0/33 

20'  2 " 

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11.21 

515 

5 

4 ' 0" 

3 1 

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51  200 

31  315 

20.48 

58.00 

— 

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51  353 

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54. /0 

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33 

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Fig.  38.— Tabulae  Statement  op  Principal  Results  op  Tests,  Series  2. 


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Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27.  Rbid  T.  Sit  wart. 


(SHOWING  THE  INFLUENCE  OF  OUTSIDE  DIAMETER  AND  THICKNESS  OF  WALL  5„  ..  SA„,  M!J).  ' PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 

ON  COLLAPSING  PRESSURE,  for  lengths  of  20  feet,  between  end  connections  cid  See  et  test  u..d.  e.n.n.,  n.m..M  NATIONAL  TUBE  CO’S.  LAP-WELDED  BESSEMER  STEEL  TUBES 

lending  to  hold  the  tube  to  a circular  form.  am, noted,  net  in  eeerege  CONDUCTED  BY  PttOF.  R.T  STEWART,  1902- d F.P.K.ItOS. 


Test 

Number 

Outside  sD'.a™e*er 

Thickness  of  Wall 

Length  of  Tube 

Weight  Of  Tube 
Lbs  per  Feat. 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis  % 

Material 

Remarks 

Commercial  Designation  of 

Tube  as  Reported. 

Nominal 

Average 

"'tZ'fff!.!' 

V ' J 

average 

At  Place  of 

As 

Repartee/ 

Actual 

. ^ 

sffnch 

• 7a  ge 
ifsed 

Rate  at 

nerru  w’ 

IbsptrSH 

Length 

f£nd 

Distance 

Tensile 
Strength 
Lbx  per  Sq  In 

Yield  Point 

Squore  Inch 

C%Ze“ 

Inches 

Reduction 
of  Area 

7. 

Silicon 

Sulphur 

Phos 

Nang. 

i .//  A . ' / . 

Op, do 

Greatest 

Least 

Greatest 

Least 

Nomina / 

Actual 

In  Feet 

InOia’s 

LU 

5 424 

i 040 

0.273 

0.246 

0.244 

to 

Li’ 

/ 4 ‘/oJ“ 

I6168 

2780 

3 

5 * 

k- 

,, 

/ 7 • 

3" 

- 25 * 

57  007 

35  360 

22.75 

54  00 



054 

0 77 

35 

.0  75 



P c 

■INI 

6 000 

5 430 

0 264 

0 274 

0 244 

. . 

20 

2f 

1 4'  lOi’ 

16  45 

2/50 

4 

5' 

6' 

1 1 

17' 

0’ 

- 145 ' 

54  580 

33  745 

24.98 

57  80 

— 

061 

.047 

35 

.075 

— 

’ c 

4 000 

5 940 

0.020 

5 460 

0 220 

0 264 

0.29/ 

0.252 

it0 

20 

2a" 

n/ot 

17  12 

16  45 

2590 

C 

2 

S’ 

0" 

10 

18' 

0" 

-145* 

65  695 

35  745 

2 1.42 

63.50 

— 

.053 

.097 

35 

.075 

— 

Be  center 

C 

Special  6' OD  17  12  lbs 

4 000 

5 .450 

0.271 

0.225 

0.250 

20  2 * 

20 

Li’ 

19' lOt 

16  55 

2460 

4 

6' 

o" 

12 

17' 

0 " 

0 0 

58  420 

36  525 

24.04 

59.40 

■■  ■ 

060 

.103 

33 

07 

— ■ 

Steel 

c 

444 

6.030 

5 450 

0.274 

0.24/ 

0253 

20 

26" 

19'lOt 

16  73 

2455 

-< 

4' 

0 * 

2 

19’ 

o" 

- 20 ' 

57  I0S 

33  57 0 

25.96 

59.60 

— 

.055 

.048 

.33 

.07 

— 

R,C 

Hy.ro, e 

5 993 

6 042 

S.tSC 

0.27 1 

0.22  5 

0.250 

20'  2i“ 

"‘Hi’ 

U.S7 

2487 

3 2 

S’  Z" 

10.4 

56  5 61 

ss  out 

23.83 

60.26 

.058 

ott 

,3d 

.073 

44  5 

10  037 

10  / 50 

9 4/0 

0 167 

0.250 

0 147 

20 

2t 

14’  /Of 

17.59 

210 

5 

8' 

6" 

10  2 

4' 

o * 

- 60* 

57  425 

35  090 

18  46 

S 2.20 

— 

.054 

1 04 

.42 

07 



P,C 

44* 

10.031 

10  120 

9 900 

0 /6 7 

0.204 

0 153 

20 

25' 

/9'IOt 

17  59 

225 

3 

1 1 ' 

o' 

13. 2 

14' 

0" 

4 22? 

55  845 

38  130 

20.92 

59  60 

— — 

.057 

.1 10 

03 

075 

— 

R.c 

' 

0-/66 

20'  O' 

26" 

19  I0i" 

B 

3 

7' 

55  405 

37  775 

20.58 

62  60 

.32 

449 

10.035 

10.150 

4.400 

0.170 

0.194 

0.  150 

20 

2h" 

17.94 

240 

5 

r 

o - 

8.4 

IS' 

6“ 

0° 

56  245 

37  845 

14  71 



.046 

.040 

.07 

_ 

s're'eT" 

*.c 

earene 

449 

10.190 

9.950 

0 157 

0 122 

0.150 

20 

it 

/f'/oi" 

16  55 

210 

5 

0 “ 

10  8 

S' 

0" 

4-  35* 

57  415 

36  475 

19.54 

59.10 

— 

.06  3 

.no 

J4 

07 

— 

R.c 

Average 

10.041 

10.149 

9 920 

0.16  5 

0.205 

0/49 

20 

>?: 

14'  /Oh’ 

17.43 

225 

4.2 

8'  4" 

10  0 

S6  477 

37  213 

14.84 

57.42 

056 

.102 

35 

.071 

450 

10.027 

10  140 

4.950 

0.206 

0.232 

0 127 

20 

iX- 

/f'/oi’ 

21  57 

425 

5 

7' 

O' 

8 4 

3' 

O' 

4 45' 

56  645 

37  105 

21.46 

57  70 

— 

.052 

.103 

.32 

.07 



R,c 

45/ 

10  024 

10  120 

4.420 

0.144 

0.2/0 

0 134 

20 

i i- 

19'  ft 

20.35 

390 

5 

8 ' 

0" 

4.6 

4' 

O' 

- 45* 

56  635 

38  7 40 

19.75 

56.80 

— 

J)9  / 

.113 

3 3 

07 

— 

R.c 

452 

10.000 

/0  00 5 

10  120 

9 970 

0 203 

0 Its 

0 292 

0 143 

20'  0 " 

20 

»r 

,9'  9 r 

21.00 

305 

e 

4 

13  2 

12 

0" 

—165“ 

58  880 

40  485 

18-38 

53.10 

080 

.118 

.27 

.07  5 

Bessemer 

10" Boiler  Tuhmg  2/  00  Lbs 

453 

10.033 

10  160 

4 420 

0 170 

0.221 

0.194 

20 

>/■ 

If  4l" 

19  44 

345 

5 

6' 

6" 

7 8 

5' 

o' 

~ 55* 

53  675 

36  455 

15. 58 

5 8.50 

— 

.087 

.104 

31 

.075 

— 

R c 

454 

10  037 

10.100 

9 4/0 

0.19  5 

0 272 

0 152 

20 

li’ 

19'  4t 

20  54 

4 00 

5 

O' 

4.6 

•7' 

O’ 

- 60° 

S3  86 5 

32  300 

22.2/ 

55 .40 

— 

091 

.100 

.28 

.07 

— 

R.  c 

f/yereg* 

10  024 

10  129 

4 944 

0 174 

0.243 

0.160 

20 

>&■ 

II ■ fS- 

20. 37 

383 

at 

»■  r 

4.7 

55  95 0 

32  7/7 

17.51 

56.30 

.078 

30 

.072 

455 

10.000 

10  100 

4 400 

0 314 

0 356 

0 301 

20 

2i" 

/4/0t 

3 3.01 

1180 

4 

u ■ 

6' 

7 8 

17' 

o' 

4 60* 

54  145 

35  505 

22.32 

54  80 

— 

.054 

047 

33 

c / 



c 

45* 

9 440 

10  090 

4.400 

0.3/2 

0.350 

0 303 

20 

25" 

/4'/0\" 

32  27 

1350 

3 

8' 

0 0 

9 6 

16' 

6" 

- 20* 

57  065 

36  135 

23  75 

55  40 

— — 

.063 

.102 

.38 

.07 

— 

, 

457 

10.000 

4 494 

10.130 

4.950 

0 300 

0 363 

0 304 

20'  O' 

20 

it 

I4l0t 

31.0  7 

3 2.7  1 

1275 

c 

4 

r 

9 0 

IS' 

4 25* 

60  360 

39  595 

22  42 

56  70 

.05  7 

105 

35 

.07 

Special  10’ OO  3/ 07  L6t 

459 

10  003 

10  100 

4.420 

0 317 

0 356 

0 310 

20 

2i" 

14’  10 1 

32  91 

1305 

4 

7' 

0" 

3.4 

7' 

6' 

- 25* 

57  440 

33  455 

23.50 

5 9.80 

— 

065 

.108 

.32 

.07 

— 

Steel 

c 

4 57 

10  023 

10.040 

4 240 

0 314 

0.391 

0 247 

20 

2f 

if'ioV 

32  61 

1385 

4 

8 ' 

0" 

4.6 

5' 

O' 

-120* 

58735 

35  725 

21.67 

58  SO 

— 

053 

.34 

07  5 

— 

£ 

Agrafe 

10  001 

10  100 

4.242 

0 316 

0 361 

0 303 

20'  2i" 

If  lei- 

32  68 

1319 

J 8 

7' 

5m 

94 

58  S 49 

35  735 

22.74 

56.44 

.058 

.104 

.34 

.071 

440 

3 440 

4.020 

3 470 

0 119 

0 132 

0 099 

20 

2 ' 

14'  Ji- 

4.91 

425 

B 

IS 

3 ' 

0 - 

4 0 

S' 

0- 

We/d  not 

5 7445 

37  240 

19  08 

55  10 

— 

041 

•J* 

.07 



R,d 

4 u 

3.490 

4.030 

3.450 

0 122 

0 134 

0 096 

20 

2 ' 

lt'  4 • 

5 06 

975 

6 

20 

3’ 

0" 

4.0 

4 ' 

6" 

found 

61  005 

44  770 

17.74 

50.10 

— 

.044 

.102 

33 

07 

— 

R.d 

442 

4 000 

3.990 

4.010 

3 970 

0 120 

0 122 

0 147 

0.  100 

20'  O' 

20 

zt 

14'  4 ’ 

4 89 

5 03 

1030 

C 

5 

4' 

3" 

12  7 

19' 

0 " 

-145* 

58  380 

34  150 

23.46 

5 7.60 

— 

043 

078 

.32 

.075 

— 

Bessemer 

c 

4 'Converse  Joint  4 84  Lbs 

44  3 

4.001 

4.0/0 

3 490 

0 120 

0.140 

0 095 

20 

2 " 

/9'  4 " 

4 98 

/ 030 

c 

5 

3’ 

3“ 

9 8 

16’ 

10" 

We/d  not 

54  240 

37  245 

5 6.00 

— 

.06  2 

.100 

.32 

.07 

— 

Steel 

d 

444 

3.442 

4 040 

3.950 

0 124 

0 049 

20 

25" 

If  3t 

4 7/ 

960 

e 

J 

4' 

0" 

12  0 

2' 

c 

found 

61  490 

45  405 

17.75 

53  7 0 

— 

063 

III 

.35 

.07 

— 

C 

fiyr.,4 

3 493 

4.022 

3.964 

0 114 

0 135 

0 095 

20 

2,i" 

If  Si- 

4.44 

464 

4.6 

3 

6' 

10.5 

58  5/0 

4/  172 

19  04 

54.50 

.052 

.09? 

34 

.071 

44  5 

4 010 

4 020 

3 990 

0 173 

0 203 

0 140 

20 

24" 

14'  4 ’ 

7 08 

2050 

5 

2' 

8" 

9 0 

18' 

7 ■ 

4 25* 

*43  70S 

*34  105 

*10.25 

*37.30 



.092 

.144 

40 

.07 



C 

444 

4 014 

4.050 

3 490 

0 172 

0.277 

0 159 

20 

24 

19  ' 4 '' 

7.28 

2225 

3 

S' 

9" 

n o 

17' 

0 " 

4 50* 

58  675 

32  075 

23.83 

5700 

— 

064 

.100 

.32 

.07 

— 

c 

447 

4 000 

4 012 

4 050 

3 460 

0 190 

0 173 

0 200 

o no 

20 ' O' 

20 

24" 

735 

7.1 1 

2425 

c 

3 

S' 

iso 

0" 

180 * 

56  005 

40  100 

19  00 

44.10 

.103 

32 

.07 

Bessemer 

Si'fnghsh  7.35  Lbs 

449 

4 019 

4.050 

4.0/0 

0 /94 

0 /92 

0 165 

20 

2t 

19  3t 

7 5 3 

2540 

3 

6 

0 " 

ii.o 

16 

0 " 

- 60* 

6/  965 

34  465 

21.21 

53 .30 

— 

.086 

.172 

29 

.0  75 

— 

Steel 

c 

444 

4.0/7 

4.040 

4.000 

0 /64 

— 

— 

20 

it 

19'  3f 

6.44 

2/60 

3 

5' 

4 * 

17.2 

I7‘ 

0" 

-125* 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

Ay.f.,9 

4.014 

4.  Cdl 

3 499 

0 /7S 

0.2/9 

0 159 

20 

24 ’ 

If  Si- 

7 17 

2280 

3.4 

S' 

0- 

15.0 

52  882 

37  3 80 

21.35 

53/3 

.085 

no 

33 

07/ 

/ 2 1 * 5 * 7 $ T 10  II  IL  13  I*  IS  It  17  1$  IT  20  2 / 22  2 3 2*  23  2 * 2 7 21  2 7 30  3!  32  33  3* 


Fig.  39.— Tabular  Statement  of  Principal  Results  of  Tests,  Series  2. 


Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 


Reid  T.  Stewart. 


(SHOWING  THE  INFLUENCE  OF  OUTSIDE  DLRME  TEH  UNO  THICKNESS  OF  WALL  *.  „„  si,..,  Nf  JJ  PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 

ON  COLLAPSING  PRESSURE,  ter  l.n,H,s  of  20  feel,  bofwoon  end  connections  d-S..  r.„  n..o  ss.„  Nf  33  NATIONAL  TUBE  CO'S  LAP-WELOEO  BESSEMER  STEEL  TUBES 


Test 

Numb  or 

Outside  Diameter 

Thickness 

of  Wall 

Length  of  Tube 
y Pear 

Weight  of  Tube 

Collapsing  Pressure 

Collapsed  Portion 

Physical  Properties 

Chemical  Analysis  % 

Material 

Remarks 

Commercial  Designation  of 

rube  as  Reported 

Nominal 

Average 

At  Place  of 

Nominal 

At  Place  of 

Col/apse 

as 

Reported 

sf.fnch 

Used 

tbiperSec 

In  F< 

Length 

End 

Tens  Ha 
Strength 
Lbs  par  Sg  In. 

Yield  Point 
Pounds  per 

Elongaticn 

S olpfll.r 

— 

Mang. 

Carbon 

— 

Least 

Greatest 

Least 

Nommol 

? et 

AM 

4 027 

.... 

„ 

0.227 

0 /81 

to 

2i' 

<*•  j }■ 

ITT 

3 12  5 

3 

3' 

o * 

1 

IS’  3" 

4/40- 

58  445 

35  7 10 

23  25 

54  70 



052 

109 

3f 

07 



d 

4.030 

0 213 

0 24  5 

0 171 

20 

py 

3j- 

8 47 

3125 

2 

2' 

83 

18'  5" 

- IkO * 

57  145 

3k  835 

24  54 

55  20 

050 

103 

33 

■ 07 

4 000 

0 22k 

0.7/0 

0 243 

0.200 

20’  0 " 

20 

2i " 

If  it 

7 00 

8 57 

3150 

D 

3' 

7 

1 1 ' o’ 

■*■110’ 

58  245 

34  SkS 

23.75 

42.50 

052 

.054 

.43 

07 

}f  Full  He.fO,  TOt  Lis 

473 

a 020 

0.2/7 

0 252 

20 

2i- 

If  jf 

8 82 

3375 

2 

2 ' 

7 ’ 

8 3 

-130° 

55  80 5 

35  475 

24.13 

55. 40 

.044 

055 

.31 

.075 

474 

4.017 

4.040 

3 770 

0.205 

0.224 

0 175 

20 

17’  4 * 

8 32 

3075 

3 

3' 

O' 

7 

4 8 - 

- 35° 

kO  280 

34  125 

22.88 

54.70 

— 

.045 

103 

.41 

025 

— 

d 

Average 

4 02k 

4 048 

4 000 

0.212 

0 238 

0.174 

20 

Pi’ 

a'  3,r 

8 43 

3170 

3 

2’  n" 

8.7 

58  372 

35  782 

23.71 

55/8 

053 

102 

37 

082 

475 

4 020 

4 030 

4 010 

0 324 

0 3 80 

0.27k 

20 

2 ' 

17' 4 " 

12.77 

5525 

2’ 

k" 

7 5 

/ ' 4" 

-120* 

57  75 0 

38  640 

22 .17 

55.30 

— 

055 

.117 

.30 

0 7 

— 

d 

47k 

4 on 

4 040 

3 780 

0 332 

0 373 

0.30k 

20 

oi ' 

17'  2 ' 

13  05 

5425 

2' 

k " 

7.5 

18'  4* 

4 25* 

575/5 

34  8 75 

23.52 

40.80 

— 

.052 

074 

28 

.08  5 

— 

d 

4 000 

4 01k 

4.030 

3.770 

0 32  1 

0 32k 

— 

— 

20’  0" 

2 0 

12  47 

12.85 

5425 

D 

10 

2' 

7 5 

1 ‘ k" 

0 * 

40  17  S 

40  875 

21.1 3 

54.20 

.043 

.070 

.28 

.08 

Bessemer 

3t'  C...4  5,,.ng  IT  47  Lbs. 

479 

4 011 

4.020 

3 770 

0 3 2k 

0 3k7 

0 3 00 

20 

ii’ 

12.85 

SkOO 

10 

2' 

3" 

i.r 

I S’ 

-*1  75° 

58  740 

37  240 

22  89 

58.20 

— - 

.044 

08b 

.31 

07 

— 

Steel 

d 

477 

4.020 

3 770 

0.328 

0.370 

0.300 

20 

,2  " 

17'  3i * 

12.87 

5425 

10 

2' 

3" 

k.8 

/'  7” 

-120’ 

54  455 

35  255 

24.83 

42.50 

— 

.053 

.104 

.33 

•08 

— 

d 

Average 

4014 

4.029 

3.772 

0 327 

0 378 

0 301 

20 

fi“ 

,fil- 

12.87 

5 5k0 

10 

2' 

5* 

7.2 

58  447 

37  501 

22-55 

57.40 

055 

.077 

30 

on 

2 777 

3 020 

2 780 

0 no 

0.1  10 

0 070 

20 

0 “ 

if  ,t 

340 

1550 

5 

3' 

0 " 

12 

18'  0 ’ 

44  400 

41  470 

17 .43 

51.50 



054 

IIP 

34 

075 



d 

3 001 

3 010 

2 770 

0.103 

0.130 

0 088 

20 

0 ’ 

if  ir 

3. 18 

* 4k5 

5 

3 ' 

O’ 

12 

18'  0 ’ 

+150’ 

— 

— 

— 

— 

— 

— 

— 

— 

— 

R,  d 

3.000 

3 00k 

3 030 

2 740 

0 107 

0.1 10 

0.1 18 

0 07k 

20'  0 " 

17 

nl’ 

if  ,f 

333 

3.40 

1 k 30 

C 

5 

2' 

3' 

18'  5’ 

+ 170* 

57  540 

4/  535 

18.00 

54.40 

052 

34 

07 

Bessemer 

3"  Slander  a Barter  Tobmg  J 33  LAs 

493 

3 001 

3 010 

2 7k0 

0.1 10 

0117 

0 077 

20 

o " 

if  if 

3.40 

1725 

5 

/ ‘ 

4* 

4 

1 ' 4* 

0* 

4/  IkO 

37  575 

20.77 

54.40 

— 

04k 

.102 

.33 

.0  7 

— 

Steel 

a 

484 

2 773 

3 000 

2.7k0 

01  II 

0.078 

20 

0 ’ 

if  if 

3.425 

2025 

5 

3' 

7' 

15 

nr 

+ 35’ 

kO  305 

42  555 

20.50 

52.10 

— - 

043 

l l l 

34 

075 

— 

d 

flvaroga 

J 000 

3.014 

2 7kk 

0.107 

on 

0.014 

20’  0“ 

if  if 

3.34 

1733 

5 

2'  8 - 

10.8 

kO  70k 

4/  537 

17.73 

54.15 

C5J 

104 

35 

073 

495 

i 78k 

3 010 

2 770 

0 112 

0.078 

20 

o’" 

if  if 

3.4  5 

1800 

5 

4' 

0“ 

lk 

II'  0 ’ 

+ 30’ 

58  285 

40  445 

21.13 

52.30 



.046 

088 

.25 

0 7 

— 

d 

49k 

2 777 

3 020 

2 770 

0 l 12 

o no 

0 072 

17 

Ill- 

if  if 

3.45 

1850 

5 

3 ' 

0“ 

12 

/'  7‘ 

57  075 

41  700 

17.13 

52.30 

— 

045 

103 

.30 

.08 

— 

a 

497 

3 000 

2 77 8 

3 020 

2 780 

0 120 

0 130 

0 07/ 

20  ’ 0 " 

Ill’ 

n if 

3 43 

3.45 

1 7k0 

c 

5 

3' 

3*' 

13 

2’  0 * 

+ 45° 

45  170 

51.70 

.040 

31 

075 

Bessemer 

3"  Locomotive  Bader  Tubmg  3 k3lks 

439 

2 778 

3 020 

2 77 0 

0 / 14 

0.1/S 

0 100 

17 

if  ,f 

3.53 

2025 

5 

3 ' 

4” 

/4 

2'  o’ 

-no’ 

42  455 

43  35 5 

17.72 

50.60 

— 

053 

112 

27 

08 

— 

Steel 

d 

497 

2 772 

3 000 

2.760 

0 113 

0 12  3 

0 104 

20 

0 " 

if  if 

3 48 

2/75 

10 

3’ 

7’ 

IS 

I7'I0" 

55  195 

42  0/5 

18.54 

57.20 

— 

0k5 

.104 

33 

075 

— 

d 

average 

2 774 

3.014 

2 770 

0113 

0.122 

0 077 

n 

III - 

„■  ,f 

347 

I7k2 

It 

3' 

km 

14 

kO  4/5 

42  4/7 

17.53 

52.72 

.050 

.100 

30 

.074 

470 

3 000 

2 777 

3 0/0 

2 790 

0.150 

0.147 

0 151 

0 138 

20’  0" 

20 

ik" 

17’  2l ’ 

4.57 

448 

3350 

o 

j 

4* 

7“ 

15'  0 " 

0* 

55  70S 

40  785 

20.42 

50.00 



074 

no 

27 

075 



Bess  Steel 

d 

Special  J’OO.  4 57  lbs 

2 78  7 

3 010 

2 770 

0 ISO 

0137 

0/37 

0./25 

20'  0 " 

20 

17'  It 

4 57 

2575 

20 

2 ' 

10 

13'  0 * 

45  705 

02  5 

07 

Average 

2 772 

3 0/0 

2.775 

0 143 

0.145 

0. 132 

2f  0 f 

If  2j- 

43k 

27k3 

3 * 8 ' 

14.5 

52  705 

35  90S 

21. 75 

53.45 

4 75 

2.770 

3 010 

2 770 

0.170 

0.2/8 

20 

ol 

If  2f 

5 48 

4200 

3 

2' 

II  5 

18'  3" 

wfVt»n:r 

70  315 

45  350 

2/25 

51.60 



071 

077 

.32 

02 

— 

d 

47k 

2 77k 

3 020 

P 780 

0 17/ 

0.2/5 

20 

If  2f 

5.  73 

4200 

3 

3’ 

k" 

14 

10’  3“ 

+ 35* 

57  455 

37  755 

20.42 

57.50 

— 

.060 

103 

3 1 

■ 02 

— 

d 

477 

3 000 

2 777 

3.020 

2 7k0 

0 180 

0 170 

0.215 

0.16/ 

20’  0 ’ 

20 

!f  2f 

5.42 

5.42 

4175 

0 

3 

3' 

3“ 

13 

13’  O’ 

55  2/5 

37  330 

22.25 

5 k. 80 

100 

.30 

.075 

Bessemer 

Speed!  3’ OD  5 42  Lbs 

478 

3 000 

3 020 

2.7k0 

0 182 

0 172 

o its 

20 

1 ’ 

If  2i- 

5.48 

3740 

5 

3' 

3” 

13 

Ik'  8" 

+ 15’ 

58  375 

34  255 

17.42 

5 7.50 

— 

,044 

.102 

.30 

07 

— 

Steel 

d 

477 

4 174 

3 000 

2 780 

0 187 

0.227 

0.170 

20 

li 

If  3 " 

5.45 

4200 

3 

3 ' 

4" 

14 

10 * 3- 

W’J‘Sdl 

42  800 

38  415 

22.4k 

57.60 

— 

.045 

.075 

.27 

07 

— 

d 

Average 

2 77$ 

1 

3 014 

2 770 

0 

0.1,0 

0 U8 

20- 

-V  2 f 

5.44 

4075 

3.4 

3' 

3" 

13.1 

kl  432 

35  02 1 

~zi7iV 

54 .28 

0,4 

.100 

3C 

0 75 

Fig.  40.— Tabular  Statement  of  Principal  Results  of  Tests,  Series  2. 


„T£  .joV  x JAory.ABO^W  10  tt&ooS  - .wiaawJ  .ihoitoasa  :?T 


hwsiwx  qw  *vta>ma  *a\rv  j*>  >0  *v.v*$v?. 

'«v\*!>  4$.  *fc.N\#vva\  vA  ,V.W2.^S  'AVA?,*^, •■/>■>. 

•a*Jv%v\'o  « »\  iA\  V\«<tv  *i\  t^«\Vt>r  *>*( 


Transactions  American  Society  of  Mechanical  Engineers,  Vol.  27. 


Reid  T.  Stewart. 


( SHOWING  THE  INFLUENCE  OF  OUTSIDE  DIAMETER  AND  THICKNESS  OF  WALL  o.n.r.t  sn.ar  Ntji.  PRINCIPAL  RESULTS  OF  COLLAPSING  TESTS  ON 

SERIES  2 < ON  COLLAPSING  PRESSURE,  for  lengths  of  20  feet,  between  end  connections  c s.'/JZ'.r  n.r  .n  e./.r.i  n.m.m  s*..r  Nt  ly.  NATIONAL  TUBE  CO'S.  LAP-WELDED  BESSEMER  STEEL  TUBES 

\ tending  to  held  the  tube  to  e eircutar  form.  CONDUCTED  BY  PROF  R.T  STCWART,  1 002-4.  FPK.I9C5. 


Ttit 

Number 

Outside  Diameter 

Thickness 

of  Wall 

Length  of  Tube 
" Feet 

Weight  of  Tube 
Lbs.por  Feet. 

Collapsing  Pressure 

Collapse , 

d Par  Hon 

Physical  Properties 

Chemical  Analysis  % 

Material 

Remarks 

Commercial  Designation  of 

Tube  as  Reported 

Nominal 

Average 

At  Ptec^  of 

Nomina / 

Average 

At  Place  of 

Cell  epee 

As 

Reported 

Actual 

Unsupported 

Round* 

Gago 

Ra,.., 

Length 

from 

Distance 
from  Weld 

Tensile 

Strength 

Lbs.perSg.ln. 

Yield  Point 
Rounds  per 
Square  Inch 

Hengetie* 

%in8 

Stlicon 

Sulphur 

Phos. 

Many 

Carbon 

Oxide 

Great**/ 

Leant  ' 

Greatest 

laaat 

Nomina/ 

Actual 

Ux>C*rS« 

In  Feet 

InDia's. 

10  771 

10  930 

10.740 

0.508 

0.570 

0.477 

If  III’ 

„■  ,■ 

55199 

2450 

s 

9'  9‘ 

7.5 

If  7 ' 

■919  5* 

54  405 

30  90S 

27.83 

57.7  0 



.050 

088 

.37 

07 



e 

5 01 

10.779 

10.910 

0.51 1 

0.593 

0.490 

15'  0" 

If  si- 

it'  2im 

5 9.099 

2575 

4 

8.7 

■9140' 

55  250 

37  210 

19.99 

90.40 

.054 

.100 

.39 

.07 

c 

602 

10  750 

1 0.707 

— 

0 500 

0 509 

0.470 

20  O’ 

n'nkm 

If  7j" 

54  25 

5 5.524 

2920 

c 

3 

' 

— 

— 

59  090 

31  245 

25.42 

57.40 

— 

.057 

.087 

.34 

.07 

— 

c 

IV'fstre  Strong  S4.25.L9x 

10.799 

10  950 

10.710 

0.509 

0.524 

0 499 

Iflli' 

55  575 

2470 

5 

7'  3" 

8.1 

3'  I" 

O' 

57  575 

33  780 

22.72 

42.10 

.051 

J2 

500 

10.797 

10.910 

10.740 

0.529 

0.579 

0.51 1 

17'  Si’ 

If  It 

57 .999 

2770 

4 

8'  0“ 

8 7 

15'  O' 

o' 

65  200 

31  47  S 

23.42 

52  50 

— 

.059 

.071 

.34 

.07 

— 

c 

Reorogo 

10.777 

10.939 

10  713 

0.512 

0.59  5 

0.497 

If  S|- 

If  3i’ 

5 9.194 

2595 

4.2 

rir 

8.7 

55  702 

32  707 

23.97 

5 4.82 

.054 

.094 

.35 

.071 

505 

12.772 

12.830 

12.730 

0.505 

0 570 

0.490 

If  II V 

IT'  IT 

99.297 

2395 

5 

10'  0 ' 

7.4 

7'  O' 

■9135' 

52  495 

31  795 

24.27 

92.40 



.057 

.097 

.33 

07 



R,C 

SOD 

12.772 

12.920 

12.710 

0.519 

0.577 

0.497 

IS'  O' 

ifni- 

If  ti- 

97.535 

2295 

5 

H'  O' 

10.4 

7'  9’ 

ISO ' 

55  405 

31  095 

22.75 

59.70 

— 

.057 

.075 

30 

.07 



R.c 

507 

12.750 

12.910 

12.990 

12.730 

0.500 

0.507 

0 529 

0.499 

20'  0* 

i fu- 

ll' 7|- 

95  00 

99.549 

2070 

c 

3 

10 ' 9" 

7 7 

55  985 

38  035 

25.75 

94.9  0 

.055 

.092 

.27 

.07 

Bessemer 

/ 2“ Extra  Strong.  85.00  Lbs. 

509 

12.774 

12.950 

12.750 

0.515 

0.552 

0 502 

lfill'. 

If  7 i‘ 

97.529 

2000 

5 

7'  O' 

8 5 

4'  9 * 

-20' 

53  7 SO 

30  80 5 

21  St 

5 1.90 

— 

.058 

09  7 

.32 

.07  5 

__ 

Steel 

pc 

507 

12.792 

12.930 

12.730 

0.513 

0. 673 

0.501 

ifni’ 

If  7 1' 

97.157 

2220 

5 

7'  9" 

8.7 

4'  7' 

ISO' 

54  395 

31  075 

24  1 3 

90.90 

— 

.055 

.092 

.32 

.0  75 

— 

R.C 

Reorego 

12  770 

12.938 

12.730 

o.5i ; 

0.598 

0.498 

ifni- 

17'  9 ' 

97.007 

2179 

4.5 

10'  0 " 

7.4 

54  394 

32  577 

23  70 

57.98 

.057 

093 

.31 

OIL 

510 

13. 042 

13.070 

12.770 

0.243 

— 

— 

20‘  0" 

17'  9i‘ 

33.300 

440 

5 

13'  O' 

12.0 

f 5' 

O' 

58  005 

35  935 

28.34 

57.40 



.08  7 

III 

.39 

.08 



R.c 

13.024 

13.070 

12.790 

0.244 

if 'lao* 

20'  0" 

17'  9i' 

33  250 

43  0 

4 

II'  0 ' 

10.2 

O' 

57  5 95 

37  245 

23.29 

57.30 

.40 

.07 

512 

13.000 

13.03 8 

13.050 

12.790 

Site  4 

0.244 

2 0*0" 

20'  O' 

17'  9i ' 

— ■ ■ — 

33.350 

SIS 

B 

5 

12'  O' 

11.1 

■9  25' 

59  880 

34  390 

2 5 43 

90.80 

.055 

.37 

.075 

Bessemer 

Hi’ Casing  if  00 

5/5 

13.039 

13.090 

12.770 

O.W.6. 

0.249 

— — 

— 

20'  0 ' 

17'  Mi- 

33.900 

490 

5 

H'  O' 

10.2 

13'  9" 

■9  10* 

91  790 

41  395 

20.17 

59.10 

— 

.048 

.102 

.34 

.08 

— 

Steel 

R.c 

5/4 

13.030 

13.090 

13.020 

0.245 

— 

— 

20'  0 " 

n'  9i" 

33.500 

450 

4 

13'  0" 

12.0 

9 ' 9 ' 

•f  30' 

59  225 

35  975 

29.21 

57.90 

— 

.052 

.087 

.37 

.075 

— 

R.c 

Rrerage 

13.039 

13.099 

12.784 

0.244 

20'  0‘ 

17'  9im 

33.400 

493 

4.9 

12'  0 * 

II. 1 

58  987 

39  979 

24.5  3 

59.94 

.051 

.100 

.38 

.0  79 

7 

9 

21 

28 

3 1 

Fig.  41.— Tabular  Statement  of  Principal  Results  of  Tests,  Series  2. 


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Vol.  27. 


Reid  T.  Stewart. 


Fia.  42.— Tabular  Statement  op  Principal  Results  op  Tests,  Series  2. 


Transaction's  American  Socnerr  or  Mechanical  Engineers,  Vol.  27. 


r 


/ 


COLLAPSING  PRESSURES  OF  LAP-WELDED  STEEL  TUBES.  95 

photographs  that  I have  here.  I have  photographs  of  all  the  tubes 
tested,  and  if  you  will  look  at  them  you  will  see  that  a long  tube 
is  only  distorted  over  a small  portion  of  its  length.  Referring  to 
the  photographs  of  tube  No.  50,  Fig.  16,  p.  30  for  example,  it  will 
be  seen  that  the  left-hand  14  feet  of  its  length  has  not  in  any 
way  been  distorted  by  the  test.  We  had  a very  precise  way  of 
determining  the  distortion  which  is  fully  explained  in  the.  paper. 
This  photograph  of  tube  No.  50  shows  clearly  that  had  we  cut 
off  a length  of  about  six  diameters  from  the  right-hand  end  of 
this  tube  and  put  it  in  the  testing  apparatus,  that  this  portion  of 
it  would  have  collapsed,  just  as  it  did  when  attached  to  the  14  feet 
that  showed  no  distortion  whatever. 

These  commercial  tubes,  taken  at  random  from  the  company’s 
stock,  were,  generally  speaking,  slightly  more  out  of  round  near 
one  end  than  elsewhere  along  their  length.  This  is  clearly  shown 
in  the  body  of  the  paper  (see  Fig.  53).  The  tubes  are  evidently 
weakest  near  one  end  on  the  average,  but  the  results  of  this  weak- 
ening influence  are  of  no  practical  importance,  not  exceeding  13 
per  cent,  and  averaging  4 per  cent,  for  a series  of  determinations 
made  for  it. 

It  is  the  practice  of  the  National  Tube  Company,  so  far  as 
I know,  to  keep  the  tubes  continually  rolling  while  cooling  down, 
so  there  is  no  chance  in  the  regular  operation  of  the  mill  for  a tube 
to  be  distorted  in  the  manner  suggested  by  the  last  speaker. 

President  Taylor. — Is  there  any  further  discussion?  If  not, 
I would  like  to  add  to  what  Mr.  Rice  has  said  in  appreciation  of 
Professor  Stewart’s  paper.  It  seems  to  me  that  the  scientific  man- 
ner in  which  the  subject  has  been  treated  is  most  worthy  of  com- 
mendation. The  fact  that  the  tubes  experimented  with  were  taken 
at  random  from  the  stock,  adds  very  greatly  in  my  opinion  to 
the  value  of  the  tests.  It  seems  to  me  that  we  should  be  very 
thankful  to  Professor  Stewart  and  to  the  National  Tube  Company 
not  only  for  making  tests  of  that  sort,  but  for  going  to  the 
trouble  of  presenting  them  to  our  Society.  It  is  just  such  papers 
as  this  which  are  of  the  greatest  permanent  interest  not  only  to 
the  members  of  the  Society,  but  to  all  Engineers  the  world  over, 
and  which  gives  our  Society  the  international  standing  which  all 
of  us  who  are  ambitious  for  the  Society  are  anxious  to  have  it 
attain. 


[HE  UBKABT  Of  [HE 
JUL  2 3 1924 

UNIVERSITY  OF  ILLINOIS 


M 


